What is this yellowish insect?

What is this yellowish insect?

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I found this insect inside of my shoe. It is approximately 1cm in length and less than half a centimetre wide. It was found in the Netherlands, in the province Gelderland.

Close shot

Distant shot

Upside down

What kind of insect is that?


As @fileunderwater suggested: the question is "close" but not identical. I think that the suggested duplicate will only provide an identification of the family of the insect, but nothing more precise and specific. Therefore, the answers for the 2 questions vary.

It is the larva of Harmonia axyridis (Asian lady beetle).

The image posted by timbernasley is more accurate because the larva you have shown is in its late instar ,a stage not an early as this one.

Here's the link: Wikipedia

This is a ladybug larva: google image search

In 1758, Carl Linnaeus described the species in the tenth edition of his Systema Naturae, giving the name Scolopendra coleoptrata, writing that it has a "coleopterated thorax" (similar to a coleopter). [3] In 1801, Jean-Baptiste Lamarck separated scutigera from scolopendra, calling this species Scutigera coleoptrata. [4] The word scutigera comes from "to bear" (gerere) and "shield" (scutum), because of the shape of the plates in the back of the chilopod. [5]

The body of an adult Scutigera coleoptrata is typically 25 to 35 mm (0.98 to 1.38 in) in length, although larger specimens are sometimes encountered. [6] Up to 15 pairs of long legs are attached to the rigid body. Together with the antennae they give the centipede an appearance of being 75 to 100 mm (3 to 4 in) in length. [6] The delicate legs enable it to reach surprising speeds of up to 0.4 meters per second (1.3 ft/s) [7] running across floors, up walls and along ceilings. Its body is yellowish-grey and has three dark dorsal stripes running down its length the legs also have dark stripes. S. coleoptrata has developed automimicry in that its tail-like hind legs present the appearance of antennae. When the centipede is at rest, it is not easy to tell its cranial end from its caudal end.

Unlike most other centipedes, house centipedes and their close relatives have well-developed faceted eyes.

House centipedes lay their eggs in spring. In a laboratory observation of 24 house centipedes, an average of 63 and a maximum of 151 eggs were laid. As with many other arthropods, the larvae look like miniature versions of the adult, albeit with fewer legs. Young centipedes have four pairs of legs when they are hatched. They gain a new pair with the first molting, and two pairs with each of their five subsequent moltings. Adults with 15 pairs of legs retain that number through three more molting stages (sequence 4-5-7-9-11-13-15-15-15-15 pairs). [8]

House centipedes live anywhere from three to seven years, depending on the environment. They can start breeding in their third year. To begin mating, the male and female circle around each other. They initiate contact with their antennae. The male deposits his sperm on the ground and the female then uses it to fertilize her eggs.

House centipedes feed on spiders, bed bugs, termites, cockroaches, silverfish, ants, and other household arthropods. They administer venom through forcipules. These are not part of their mandibles, so strictly speaking they sting rather than bite. They are mostly nocturnal hunters. Despite their developed eyes, they seem to rely mostly on their antennae when hunting. Their antennae are sensitive to both smells and tactile information. They use both their mandibles and their legs for holding prey. This way they can deal with several small insects at the same time. To capture prey they either jump onto it or use their legs in a technique described as "lassoing". Using their legs to beat prey has also been described. [9] Like other centipedes they can stridulate.

In a feeding study, S. coleoptrata showed the ability to distinguish between possible prey, avoiding dangerous insects. They also adapted their feeding pattern to the type of hazard the prey might pose to them. For wasps, they retreat after applying the venom to give it time to take effect. [9] When the centipede is in danger of becoming prey itself, it can detach any legs that have become trapped. House centipedes have been observed to groom their legs by curling around and grooming them with their forcipules.

In 1902, C. L. Marlatt, an entomologist with the United States Department of Agriculture, wrote a brief description of the house centipede: [1]

It may often be seen darting across floors with very great speed, occasionally stopping suddenly and remaining absolutely motionless, presently to resume its rapid movements, often darting directly at inmates of the house, particularly women, evidently with a desire to conceal itself beneath their dresses, and thus creating much consternation.

Outdoors, house centipedes prefer to live in cool, damp places. Centipede respiratory systems do not provide any mechanism for shutting the spiracles, and that is why they need an environment that protects them from dehydration and excessive cold. Most live outside, primarily under large rocks, piles of wood or leaves, in barkdust and especially in compost piles. They often emerge from hiding during the watering of gardens or flowerbeds. These centipedes can be found in almost any part of the house although they are usually encountered in dark or dimly lit areas such as basements and garages. Inside the home, they can be found in bathrooms and lavatories, which tend to be humid, but they can also be found in drier places like offices, bedrooms and dining rooms. They are usually seen crawling along the ground or floor, but they are capable of climbing walls. The greatest likelihood of encountering them is in spring, when they emerge due to warmer weather and in autumn/fall, when the cooling weather forces them to seek shelter in human habitats.

S. coleoptrata is indigenous to the Mediterranean region, but it has spread through much of Europe, Asia, North America and South America. It is thought to have first been introduced to the Americas in Mexico and Guatemala and now it reaches north into Canada and south to Argentina. [9]

In the United States, it spread north from the southern states, reaching Pennsylvania in 1849, New York in 1885, and Massachusetts and Connecticut in about 1890. In 2009, its distribution extended from Virginia in the east to the coast of California in the west. It is also found in the Pacific Northwest, where it appears to be somewhat less common than in other areas of the country. [ citation needed ]

In 2011, it was first reported in Chile, in the Metropolitan and Los Lagos regions. [10]

In 2013 they were recorded in Lichinga, Mozambique, and in 2017 in Pemba and at Lujeri Tea Estate, Mulanje, Southern Malawi. [ citation needed ]

They have been found in eastern and southern Australia, from Perth to Adelaide, South Australia, to Sydney, New South Wales and in Tasmania. Other countries they have been found in include New Zealand, [11] Japan [ citation needed ] and South Korea [ citation needed ] .

Although known to exist in South and Southeast Asia, S. Coleoptrata is relatively rare. [ citation needed ]

The faceted eyes of S. coleoptrata are sensitive to daylight and very sensitive to ultraviolet light. [12] They were shown to be able to visually distinguish between different mutations of Drosophila melanogaster. [13] How this ability fits with its nocturnal lifestyle and underground natural habitat is still under study. They do not instantly change direction when light is suddenly shone at them, but will retreat to a darker hiding spot.

Some of the plates covering the body segments fused and became smaller during the evolution to the current state of S. coleoptrata. The resulting mismatch between body segments and dorsal plates (tergites) is the cause for this centipede's rigid body.

Relation between body segments, dorsal plates (tergites), and leg pairs
Tergite 1 2 3 4 5 6 7 8 9 10 11
Segments 1 2 3, 4 5, 6 7, 8, 9 10, 11 12, 13 14, 15 16 17 18
Leg pairs Forcipules 1 2, 3 4, 5 6, 7, 8 9, 10 11, 12 13, 14 15 (antenna-like snare legs) (gonopod) (anus)

Tergites 10 and 11 are not fully developed and segment 18 does not have a sternite. This model deviates from descriptions by Lewis who identified only 7 tergites and 15 segments. [14]

Another feature that sets S. coleoptrata apart from other centipedes is that their hemolymph was found to contain proteins for transporting oxygen.

The mitochondrial genome of S. coleoptrata has been sequenced. This opened up discussions on the taxonomy and phylogeny of this and related species. [15]

Unlike its shorter-legged but much larger tropical cousins, S. coleoptrata can live its entire life inside a building, usually the ground levels of homes. Though they often startle their unwitting housemates with their appearance and surprising speed, [16] they are not generally considered dangerous to humans. House centipedes typically flee when disturbed and bites are uncommon unless provoked. Its jaws have difficulty penetrating human skin, and its bite and venom rarely produce more than temporary, localized pain no worse than a bee sting. [6] [17]

I just found this insect and I don't know what is it. It seems to be the larva of a fly or maybe a little butterfly. I live in Spain so it is fall. What should I do with it?

Looks somewhat like a pillbug (an isopod, not an insect) to me, but can't really tell from the picture.

Need more information:
Where did you find it?
Is it aquatic or terrestrial (can't tell from picture)?
Does it have legs? How many? Insects have 6 legs when mature.
Is it flat or round in cross section?

Looks somewhat like a pillbug (an isopod, not an insect) to me, but can't really tell from the picture.

Need more information:
Where did you find it?
Is it aquatic or terrestrial (can't tell from picture)?
Does it have legs? How many? Insects have 6 legs when mature.
Is it flat or round in cross section?

I found it in the wall of my room (I live in a flat near a river)
It's about 4-5 mm long and 1'5 mm wide.
It seems to be terrestrial.
It has 6 legs in the upper half and it's yellowish white below.
The shape is like a flattened cylinder.

I dont want to leave it on the street how I fed it?

What is this yellowish insect? - Biology

Yellow Jackets are a type of wasp. Many people mistake these small wasps for bees as they are similar in size and coloring to honey bees, but they are actually from the wasp family.

What does a Yellow Jacket look like?

Yellow Jackets are yellow and black with stripes or bands on their abdomen. Workers are typically around ½ inch long. Like all insects yellow jackets have six legs and three major body parts: the head, thorax, and abdomen. They have four wings and two antennae as well.

Can Yellow Jackets Sting?

Yellow jackets have a stinger at the end of their abdomen. Unlike honey bees, a yellow jacket's stinger doesn't usually come out when stinging, allowing it to sting several times. As a result, disturbing a yellow jacket nest can be very dangerous! Some people are allergic to the venom in a yellow jacket sting and should seek medical help immediately.

Where do Yellow Jackets live?

Different species of yellow jackets are found throughout the world. In North America the European Yellow Jacket (German Wasp), the Eastern Yellow Jacket, and the Southern Yellow Jacket are very common. Yellow jackets live in hives or nests of large colonies. Depending on the species, nests will either be underground or in somewhat protected areas like a hollowed out tree or an attic in a building. They build their nests in layers of six-sided cells out of wood they have chewed up into a pulp. When dry, this pulp becomes a paper-like substance.

A colony of yellow jackets is made up of workers and the queen. The queen stays in the nest and lays eggs. The worker's job is to protect the queen, build the nest, and retrieve food for the queen and larvae. Nests grow over time to around the size of a soccer ball and can house 4,000 to 5,000 yellow jackets. Nests are usually lived in for one season as the colony dies off in the winter.

What do Yellow Jackets Eat?

Yellow Jackets primarily eat fruit and plant nectar. They have a proboscis (sort of like a straw) that they can use to suck juices from fruit and other plants. They are attracted to human food as well such as sweet drinks, candy, and juices. Sometimes they will eat other insects or try to steal honey from honey bees.

How to live with solitary wasps

Managing solitary wasps is difficult and is unnecessary. Remember, these wasps are beneficial with little risk of stings.

If you find solitary wasps in your landscape:

  • Ignore and tolerate them whenever possible.
  • Solitary wasps are active for just a few weeks.
  • They only live one season and do not reuse nests year after year.
  • Solitary wasps are not aggressive and are unlikely to sting.

Solitary wasps can sometimes still cause concern when found nesting where people, especially children, are present. In cases where it is difficult for residents to ignore the nests, there are few options that can be attempted.

Management options in turf

In lawn areas, the best management is to treat each individual nest with insecticidal dust labeled for ground-nesting insects, e.g. permethrin. Spraying the nest area with a liquid insecticide is not very effective.

Management options in playgrounds or sandboxes

Sand wasps or other digger wasps that nest in sandboxes or playgrounds are difficult to manage once they have started nesting. Using a pesticide where children play is not recommended.

It might be possible to discourage wasps from nesting in an area.

  • Frequent raking of the nesting area may cause them to nest somewhere else.
  • Laying a tarp over the nests for several days may also discourage them from that area.

Mud dauber nests

When mud dauber nests are found on a home, ignore them or remove the nests with a putty knife. They do not defend their nests so there is little to no risk of stings.

White Peach Scale

White peach scale, Aculus ligustri (Keifer) Eriophyidae, PROSTIGMATA


Adult &ndash The female scale is 1 to 2.25 mm in diameter, circular, convex, and thickened. It is white, yellowish white, or grayish white with a yellow or reddish spot (the cast skin of the nymph). The male adult scale is a small, two-winged insect that looks like a gnat but has two tail filaments.

Egg &ndash The female egg is coral colored, and the male egg is pinkish white. The tiny eggs are found beneath the female scale.

Nymph &ndash The female nymphal scale looks like the adult but is smaller and lacks the spot on the scale. The male nymph is elongate oval, white or dirty white, and about 1 mm long. Crowding and particular host plants can affect the shape and color of the scale considerably.

Distribution &ndash The white peach scale is found throughout the southern part of the United States and as far north as Connecticut.

Host Plants &ndash As its name implies, the white peach scale is a pest of peach. However, this insect feeds on many other plants of economic and ornamental value. Some of the most frequently infested ornamentals are chinaberry, flowering peach, French mulberry, and persimmon but other hosts include catalpa, lilac, privet, and walnut.

Damage &ndash The white peach scale feeds on the bark, fruit, or leaves of the host plant. Its feeding can cause stunting, leaf drop, and death of entire branches.

Life History &ndash Overwintering as adult females, white peach scales become active in the spring and begin depositing eggs about April 1 in the Southeast. The insects continue laying eggs for approximately 30 days. Female eggs are produced before male eggs during the sequence of egg-laying. In 3 or 4 days, the eggs hatch into young nymphs or crawlers. Female crawlers are more active than their male counterparts. The crawlers settle and begin feeding within 2 days. The first nymphal stadium lasts 7 or 8 days. The second female nymphal stadium lasts about 12 days. The adult emerges after the second molt. Second instar male nymphs molt about 5 days after their first molt and then emerge from their scales in 7 or 8 days as adults. The emergence of the male scale and the final molt of the female scale coincide. After molting, male scales die within 24 hours. Fourteen to 16 days after mating, the females begin to lay eggs. At 25°C, a generation is completed in 35 to 40 days. There are three generations per year in the Southeast. Because mortality of the first and second generations is high, the movement of the scale to other plants occurs mostly during the third generation in September and October.

Because the insect may be found on the undersurfaces of branches, it is important to treat all infested areas on the plant. For specific chemical controls, see the current state extension recommendations.


This plant grows to about 30–60 cm (12–24 in) high, with a maximum of 1 m (3 ft 3 in). The stem is ribbed and hairless, branched at the base. It has basal rosettes of shiny, dark green leaves. The basal leaves are stalked and lyre-pinnatifid, that is with a large terminal lobe and smaller lower lobes. The cauline leaves are smaller, ovate, toothed, or lobed. The flowers are borne in spring in dense terminal clusters above the foliage. They are 7–9 mm (0.28–0.35 in) long, with four bright yellow petals. The flowering period extends from about April through July. The fruit is a pod around 15–30 mm (0.59–1.18 in).

Chemical substances in this species include saponins, [2] [3] [4] [5] flavonoids, [6] and glucosinolates. [7] [8]

It was first published and described by William Aiton in his 'Hortus Kewensis' Vol.4 on page 109 in 1812. Some references mention Robert Brown (Robert Brown (botanist, born 1773)), [9] as the author but there are no mentions of his name in Hortus Kewensis, so Aiton is regarded as the correct author. [10]

It has various common names including 'bittercress', 'cressy-greens', 'herb-Barbaras', 'rocket cress', 'upland cress', 'English wintercress' and 'yellow rocket'. [11]

Etymology Edit

The genus name Barbarea derives from Saint Barbara, the patron saint of artillerymen and miners, as this plant in the past was used to soothe the wounds caused by explosions. [12] The species Latin name vulgaris means “common”. [13]

Most B. vulgaris genotypes are naturally resistant to some insect species that are otherwise specialized on the crucifer family. In the case of diamondback moth (Plutella xylostella) and the flea beetle Phyllotreta nemorum, the resistance is caused by saponins. [2] [3] [4] [5] Glucosinolates such as glucobarbarin and glucobrassicin are used as a cue for egg-laying by female cabbage white butterflies such as Pieris rapae. Indeed, the larvae of this butterfly thrive well on this plant. Diamondback moth females are also stimulated by these chemicals, but the larvae die due to the content of saponins which are apparently not sensed by the moths. This phenomenon has been tested for biological insect control: B. vulgaris plants are placed in a field and attract much of the diamondback moth egg load. As the larvae die shortly after hatching, this kind of insect control has been named "dead-end trap cropping". [14]

Native to Eurasia and North Africa, it is naturalised in many parts of North America and New Zealand as a weed. [11]

Range Edit

It is found in temperate North Africa within Algeria and Tunisia. Also in Asia, within Afghanistan, Armenia, Azerbaijan, the Caucasus, China (in the provinces of Heilongjiang, Jiangsu, Jilin and Xinjiang), Georgia, Iran, Iraq, Japan (in the provinces Hokkaido, Honshu, Kyushu, Ryukyu Islands and Shikoku), Kazakhstan, Kyrgyzstan, Mongolia, Siberia, Tajikistan, Turkmenistan and Turkey. It is also found in tropical parts Asia, such as India (- in the provinces of Sikkim, Himachal Pradesh, Jammu and Kashmir, Tamil Nadu, Uttar Pradesh and Arunachal Pradesh), Pakistan and Sri Lanka.

The plant prefers fresh or moist places, on roadsides, along rivers, in arable land, wastelands and docklands, or on the slopes and in ditches, at an altitude of 0–2,500 m (0–8,202 ft) above sea level. [1]

It also prefers to grow in siliceous, calcareous, sandy, alluvial and clay soils. [1]

A pubescent type (the "P-type") has been described from southern Scandinavia and Russia. While this chemotype is rare in Scandinavia, it seems to be dominant in Russia according to the only survey made so far. [15] This type has atypical chemistry and is devoid of resistance to the diamondback moth and the flea beetle Phyllotreta nemorum. The P-type belongs morphologically to the variety B. vulgaris var. arcuata, but may also be identical to the subspecies originally described as Barbarea arcuata Rchb. ssp. pubescens N. Busch. In this context, the usual type of B. vulgaris var. arcuata is called the "G-type" (for glabrous (hairless) leaves). This type is reported to be dominant in Central Europe. [15] On a genomic scale, more than 22.000 genes (89% of those tested) were found to have fixed differences between the two types. [16]

A chemotype with deviating glucosinolate content has been described from Western and Central Europe and named the "NAS-type" (because it is dominated by the glucosinolate glucoNASturtiin. This type has increased resistance to some specialized insects. In this context, the usual chemotype of B. vulgaris is called the "BAR" type (because it is dominated by glucoBARbarin). [17]

While the P-type and G-type differ in multiple genetic, chemical and morphological features, the NAS and BAR types seem to be a simple monogenic variation. [17] For this reason, it has been suggested to refer to NAS and BAR forms (from the lowest botanical rank forma) and P- and G-types. Indeed, occasional NAS form plants in Central Europe were found to be G-type by a set of genetic markers. [18]

The young leaves can be eaten raw or cooked. [19] The buds and flowers are also edible. [20] It can also be used as a dead-end trap crop for diamondback moth, the caterpillar of which is a pest on cruciferous plants like Cabbage. [21]

Graphical abstract

Lepidopteran insects exhibit remarkably diverse colors and patterns that have gained the attention of scientists for centuries hence, numerous studies regarding wing color and pattern characteristics have been conducted (Monteiro, 2015). Similar to the wings of adult individuals, lepidopteran larvae show diverse color patterns to better adapt to their habitats. However, information regarding the molecular regulation of larval body colors and patterns is limited.

Melanin pigmentation is a variable trait that plays an essential role in physiological processes and visual interactions, both between members of the same species and between members of different species (True, 2003 Wittkopp and Beldade, 2009). The yellow-y gene, one of the melanin synthesis pathway genes, is required for black pigmentation the Yellow-y protein is also highly expressed in developing adult epidermal cells fated to produce black pigmentation in Drosophila (Gompel et al., 2005 Walter et al., 1991 Wittkopp et al., 2002a, 2002b). In the domestic silkworm Bombyx mori and the swallowtail butterfly Papilio xuthus, the expression patterns of the yellow-y gene correspond to black pigmentation patterns during the larval stages (Futahashi et al., 2008 Futahashi and Fujiwara, 2007). Futahashi et al. (2008) have demonstrated that B. mori yellow-y is responsible for the spontaneous larval color mutant, chocolate (ch) (Fig. 1A). Hence, it is likely that the yellow-y gene serves crucial functions in larval pigmentation and color patterns across broad taxa of lepidopteran insects.

The yellow gene family, including yellow-y, is a large and diverse group and represents a rapidly evolving gene family having pleiotropic functions in addition to pigmentation. The protein product of yellow-y in the brains of Drosophila melanogaster plays a necessary role in normal male courtship behavior (Drapeau et al., 2003). The major royal jelly proteins (MRJP), which are also members of the yellow family, have been isolated from the brain, venom glands, and tissues in different developmental stages in the honeybee, suggesting that they are multifunctional proteins with diverse, context-dependent physiological and developmental roles (Drapeau et al., 2006 Peiren et al, 2005, 2008 Schmitzova et al., 1998). In Tribolium castaneum, yellow-f appears to be necessary for adult cuticle sclerotization, whereas yellow-e has a vital role in waterproofing, in addition to their roles in normal pigmentation (Arakane et al., 2010 Noh et al., 2015). Although yellow family genes appear to have important and pleiotropic functions, the physiological functions of yellow genes are largely unknown.

The tobacco cutworm Spodoptera litura is a destructive polyphagous pest and has developed a high resistance to insecticides (Sparks and Nauen, 2015). We considered S. litura suitable for investigating the functions of the yellow-y gene for two reasons: (1) S. litura has a dark-brown or blackish body color during the late larval stages (Fig. 1B) thus, the S. litura yellow-y gene is expected to play an essential role in larval body coloration and (2) fully assembled genome sequences of S. litura have been made available (Cheng et al., 2017).

Although RNA interference is one of the most well-known strategies for analyzing functional genomics, this technique is not efficient in Lepidoptera (Terenius et al., 2011). The CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9) system is a powerful genome editing tool used to introduce targeted gene mutagenesis into genomic DNA (gDNA) via microinjection into preblastoderm embryos and has been widely used in many animals and plants (Doudna and Charpentier, 2014 Hsu et al., 2014). Several studies have recently reported successful CRISPR/Cas9-mediated gene editing in S. litura, which showed high mutagenesis and target specificity (Bi et al, 2016, 2019, 2016 Xu et al., 2020 Zhu et al., 2016, 2017). Therefore, we adopted the CRISPR/Cas9 system to elucidate the functions of yellow-y in S. litura.

In the present study, we first identified yellow-y and other yellow family genes expressed in S. litura. Next, we examined the temporal expression patterns of yellow-y during the larval–larval molting stages. To explore the roles of the S. litura yellow-y gene, CRISPR/Cas9-mediated targeted gene mutagenesis was conducted, and a yellow-y deficient mutant strain was successfully established. We demonstrated that the function of yellow-y in pigmentation is evolutionarily conserved in lepidopteran insects and also showed species- and tissue-specific requirements of yellow-y in pigmentation in comparison with those of B. mori yellow-y mutants. Furthermore, we found that almost none of the yellow-y mutant embryos hatched unaided. Therefore, we concluded that S. litura yellow-y has a novel important function in egg hatching in addition to pigmentation.


Photo by:
J. H. Robinson/Photo Researchers, Inc.

Whiteflies usually occur in groups on the underside of leaves. The adults of most species are similar in appearance and are shaped like tiny moths. Most are less than about 2 mm (0.08 in) long. The body is usually yellowish, but the insects look white because of a mealy wax that covers the wings and body.

Females lay tiny, oblong eggs, usually on the underside of leaves. Eggs hatch into barely visible, oblong yellowish nymphs known as crawlers. After hatching, crawlers soon pierce the host plant with their needlelike mouthparts and remain settled on the plant until adulthood. The semitransparent nymphs become flattened and oval after the first molt, or shedding of the skin. They are covered with a waxy secretion and look like tiny scale insects.

Mature nymphs become temporarily inactive during the last growth stage. This stage is commonly called a pupa, even though whiteflies have incomplete metamorphosis and do not have a true pupal stage. The appearance of these "pupae" is used to distinguish among species of whiteflies. The pupal cover varies from transparent to whitish and may be either smooth or covered with curly wax scales.

Most species of whitefly have several generations each year, with all stages present year-round on the same host plant in areas with mild winters. The time required for whiteflies to complete a single generation can vary from several months during the winter to a few weeks during summer.

Whiteflies suck the flowing sap, or phloem, of plants. High populations of these insects may cause leaves to yellow, shrivel, and drop prematurely. The excess sap or sweet honeydew excreted by nymphs collects dust, leads to growth of sooty mold, and attracts ants. Like many other species in the aphid and cicada order, whiteflies can transmit viruses to plants.

Most whiteflies are uncommon because of natural controls, such as parasitic wasps and predaceous beetles, bugs, and lacewings. The few species that are pests occur primarily in greenhouses and outdoors in mild-winter areas. The greenhouse whitefly is a common pest of many ornamental plants, especially in greenhouse environments. It is sometimes controlled by release of parasitic wasps. The sweetpotato whitefly is a serious pest of many agricultural field crops. Recent outbreaks of this species in California and Texas have caused million of dollars' worth of damage. In extreme cases, the air around infested fields may be filled with choking, dustlike clouds of adult whiteflies.

Scientific classification: Whiteflies are in the family Aleyrodidae, order Homoptera. The greenhouse whitefly is classified as Trialeurodes vaporariorum and the sweetpotato whitefly as Bemisia tabaci.

What is this yellowish insect? - Biology

The thorn bug is an occasional pest of ornamentals and fruit trees in southern Florida. During heavy infestations, nymphs and adults form dense clusters around the twigs, branches and even small tree trunks. Some hosts that have been severely damaged include Hibiscus sp., powder-puff (Calliandra spp.), woman's tongue tree (Albizzia lebbek), and Acacia spp. Young trees of jacaranda (Jacaranda acutifolia) and royal poinciana (Delonix regia) with a diameter of 1.5 to 2 inches have been killed by thorn bugs in the Tampa area. The trunks were so heavily infested that is was difficult to place a finger anywhere on the trunk without touching a specimen.

The thorn bug causes damage by piercing the plant tissue and sucking the sap and by making cuts in the plant for oviposition. Butcher (1953) reported that certain trees, especially some cassias, suffered considerable loss of foliage, and that pithecellobiums (Pithecellobium spp.) suffered general and extensive terminal twig death. He also mentioned that thorn bug honeydew secretions and accompanying sooty mold development caused a nuisance to home owners. Kuitert (1958) noted that heavy accumulations of honeydew sometimes occurred on parked automobiles.

Figure 1. Adult female thorn bug, Umbonia crassicornis (Amyot and Serville). Photograph by Lyle J.Buss, University of Florida.

Distribution (Back to Top)

This thorn bug has been found throughout South and Central America, Mexico, and southern Florida. The Van Duzee (1917) records of Umbonia crassicornis in Ohio and South Carolina are puzzling. At best, these would seem to be accidental introductions in which no natural populations were maintained. In Florida, as of 1962, no thorn bugs were collected north of Winter Haven or south of Florida City according to Division of Plant Industry and University of Florida Agricultural Experiment Station records. However, the range of some of the hosts exceeds the range of the thorn bug. The original description in 1843 suggested that Umbonia crassicornis was present in Florida at that time, but this species apparently did not become abundant until the last 15 years. Butcher wrote that his first specimens were obtained in April 1951. In a personal letter, Nov. 7, 1962, Dr. E.G. Kelsheimer said, "Our first experience with the thorn bug was in 1948 at Delray Beach where it was thriving on Pithecellobium sp. At that time it was unknown on the west coast, but the next time it was reported to us from Fort Myers where it apparently came in on nursery stock. From Fort Myers it gradually worked its way up to Bradenton."

Identification (Back to Top)

Four species of Umbonia are present in the U.S., but they are only found in the subtropical regions (Arnett 2000). The most common is Umbonia crassicornis.

The thorn bug is a variable species as to size, color and structure, particularly the pronotal horn of males. Typically, the adult is about 0.5 inch in length and is green or yellow with reddish lines and brownish markings. Other treehoppers sometimes mistaken for the thorn bug in Florida are the varieties Quadrivittata (Say) and Sagittata (Germar) of Platycotis vittata (Fabricius). These varieties have the pronotal horn, but other varieties of Platycotis vittata do not (Cook 1955).

Figure 2. Adults of the thorn bug, Umbonia crassicornis (Amyot and Serville), showing variation in the species. Females are above, males are below. Photograph by Lyle J.Buss, University of Florida.

The horned specimens exhibit a low, forward-projecting anterior pronotal process as opposed to either the tall, essentially perpendicular horn of the female thorn bug or the high receiving horn of the male. The humeral processes of the thorn bug are larger than those of Platycotis vittata. Platycotis vittata lives primarily on oak (Quercus spp.) in Florida, whereas DPI has no reports of the thorn bug on oak.

Figure 3. Adults and nymph of the thorn bug, Umbonia crassicornis (Amyot and Serville). Males, A-C Female - D Nymph - E. Photograph by Division of Plant Industry.

Biology (Back to Top)

Females lay their eggs in the tender bark of twigs and the eggs hatch about 20 days later. The female actively tends her brood or colony, which can number from 15 to 50 individuals. Young nymphs have three horns instead of the one seen on the adults. While four generations occur per year, females lay only a single clutch of eggs. (Johnson and Lyon 1994).

The species has a chemical communication that aids in the defense of the young. This chemical passes between the parent and nymphs, making them distasteful to potential predators (Johnson and Lyon 1994).

Hosts (Back to Top)

In addition to the above species, immatures and adults have been found on wild tamarind (Lysiloma bahamensis), tamarind (Tamarindus indica), Casuarina sp., Crotalaria sp., rayado bundleflower (Desmanthus virgatus), bottle brush (Callistemon sp.), Jerusalem thorn (Parkinsonia aculeata), dwarf date palm (Phoenix roebeleni), and from Steiner traps placed in a variety of trees. Adults have been reported on Citrus spp., Bidens pilosa, bagpod (Sesbania vesicaria) or (Glottidium vesicarium), avocado fruit (Persea americana), holly (Ilex sp.), lychee (Litchi chinensis), Caesalpinia sp., and Mimosa sp.

Seasonal Distribution (Back to Top)

Adults and nymphs can be found all year. Reports of heavy infestations have been received in all seasons, but probably more have come in during the cooler months. Cyclic phenomena also may play a part.

Management (Back to Top)

Due perhaps to the sporadic nature of the thorn bug, experimental work on the control of this pest is very limited.

Selected References (Back to Top)

  • Arnett Jr RH. 2000. American Insects: A handbook of the insects of America north of Mexico. CRC Press. Boca Raton. 1003 pp.
  • Butcher FG. 1953. Unusual abundance of the tree-hopper Umbonia crassicornis A. & S. Florida Entomologist 36: 57-59.
  • Cook Jr PP. 1955. Notes on nomenclature and variation in Platycotis. Pan-Pacific Entomologist 31: 151-154.
  • Goding FW. 1929. The membracidae of South America and the Antilles. IV. Sub-families Hoplophorioninae, Darninae, Smiliinae, Tragopinae (Homoptera). Transactions of the American Entomological Society 55: 202-205.
  • Goding FW. 1930. An injurious membracid. Journal of the New York Entomological Society 38: 47.
  • Johnson WT, Lyon HH. 1994. Insects that feed on trees and shrubs. Cornell University Press. pp. 1-560.
  • Kuitert LC. 1958. Insect pests of ornamental plants. University of Florida Agricultural Experiment Station Gainesville Bulletin 595: 14-15.
  • Maxwell LS. 1959. Handbook of Florida insects and their control. Great Outdoors Publishing Co., St. Petersburg, Florida. p. 33.
  • Van Duzee EP. 1917. Catalogue of the Hemiptera of America north of Mexico, excepting the Aphididae, Coccidae and Aleurodidae. University of California Agricultural Experiment Station Technical Bulletin, Entomology 2: 557-558.

Authors: F.W. Mead (retired), Florida Department of Agriculture and Consumer Services, Division of Plant Industry and Thomas R. Fasulo, University of Florida.
Originally published as DPI Entomology Circular 8. Updated for this publication.
Photographs: Lyle J. Buss, University of Florida and Division of Plant Industry
Web Design: Don Wasik, Jane Medley
Publication Number: EENY-175
Publication Date: November 2000. Latest revision: August 2014. Reviewed: December 2017. Reviewed: May 2021.

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Featured Creatures Editor and Coordinator: Dr. Elena Rhodes, University of Florida