Category Archives: Entomology

Badass females are unpopular among praying mantids

by Piter Kehoma Boll

One of the most iconic representations of praying mantids is that of a female eating the male after (or during) sex, an unpleasant scenario that starts with a beheading before the poor male even finishes his job.

Mantismeal

Delicious male meal. Photo by Wikimedia user Classiccardinal.*

According to some studies, when the male is beheaded, he increases the pumping of semen into the female, thus increasing the chances of fecundation. This could make one think that being eaten is actually an advantage to the male, as it makes him have more offspring.

Several observations with different species show the opposite though. Males make everything they can to avoid being eaten by the female, as it allows them to copulate with additional females. But how can they escape from such a gruesome destiny?

It is known that hungry females are more eager to eat the partner than satiated ones. Well-fed females (fat ones) are also less likely to have a meal in bed than malnourished ones. Males can tell whether a female is hungry or malnourished and thus avoid those in such conditions. They like fat and fed females. But this is not the only thing that males take into account when choosing the appropriate mother for their children.

A study from 2015 by researchers of the University of Buenos Aires have shown that males of the species Parastagmatoptera tessellata, found in South America, also choose females based on their personality.

In a laboratory experiment, a male was put in a container where he could see two females, one aggressive and one non-aggressive. Another male was presented to both females (which were unable to see each other) and the aggressive female always attacked the male, while the non-aggressive one never did. After watching how each female behaved, the male received access to both and could choose his favorite one.

And guess what? The non-aggressive one was chosen most of the time. This means that males are not only able to tell whether they are likely to be eaten based on the female’s hunger and nutritional condition, but also by analyzing the behavior of the female towards other males.

See also:

Gender conflict: Who’s the man in the relationship?

Male dragonflies are not as violent as thought

– – –

ResearchBlogging.orgReferences:

Lelito, J., & Brown, W. (2008). Mate attraction by females in a sexually cannibalistic praying mantis Behavioral Ecology and Sociobiology, 63 (2), 313-320 DOI: 10.1007/s00265-008-0663-8

Scardamaglia, R., Fosacheca, S., & Pompilio, L. (2015). Sexual conflict in a sexually cannibalistic praying mantid: males prefer low-risk over high-risk females Animal Behaviour, 99, 9-14 DOI: 10.1016/j.anbehav.2014.10.013

– – –

*Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

Leave a comment

Filed under Behavior, Entomology, Zoology

Don’t let the web bugs bite

by Piter Kehoma Boll

If you think spiders are scary creatures, today you will learn that they are scared too. But what could scary a spider? Well, a web bug!

We usually think of spider webs as an astonishing evolutionary achievement of this group of arachnids and a very efficient way to capture prey without having to pursue them. Webs are sticky, resistant, and only spiders themselves can move freely through them. The only problem is that this is not true.

emesaya_feeding

A thread-legged assassin bug (Emesaya sp.) feeding on a spider after invading the spider’s web in the Western Ghats, India. Photo by Vipin Baliga.*

A group of bugs that conquered the spider world are the so-called thread-legged assassin bugs, which comprise the subfamily Emesinae of the assassin bugs (family Reduviidae). As the name implies, the assassin bugs are a group of true bugs (suborder Heteroptera) that are expert killers of other creatures.

During their evolution, the thread-legged assassin bugs seem to have acquired a special taste for spiders and throughout the world they are usually associated with this eight-legged predators. In many cases, such as the one seen in the picture above, the bugs prey on the spiders, having developed the ability to move through the webs. They usually produce vibrations on the web that attract the spiders. Those, thinking that they caught a prey, are lured directly to their death in the legs and proboscis of the terrible bug.

Some thread-legged assassin bugs have, however, found another way to harass spiders: by stealing their food. In the latter scenario, the bugs usually wait close to or on the spider’s web and, when an insect is caught, they steal it from the spider by ripping it off the web. This kind of behavior is called kleptoparasitism, which means “parasitism by stealing”.

But how can spiders avoid this bug nightmare?

Until recently, it was thought that spiders were safe inside caves. Although emesinid bugs do occurr in caves, their association with spiders seemed to be weaker or non-existent there. But new findings are revealing that they pursue our arachnid fellows even to the deepest abysses of Earth.

The earliest cave-dwelling thread-legged assassin bug known to prey on spiders is Bagauda cavernicola, from India. Its spider-eating habits are known since the first decades of the 20th century.

The second species, Phasmatocoris labyrinthicus, was found almost a century later, in 2013, in Arizona, USA. More than only preying on spiders, such as the species Eidmanella pallida that lives in the same cave, P. labyrinthicus seem to have developed the ability to manipulate abandoned spiderwebs and use them to detect and capture prey for their own consumption. Only a single instance of such a behavior has been recorded and the species’s behavior needs further studies.

phasmatocoris_labyrinthicus_eating

Phasmatocoris labyrinthicus feeding on the spider Eidmanella pallida in the Kartchner Caverns, Arizona, USA. Photo extracted from Bape, 2013.

Now, only 3 years later, there are new evidences of more thread-legged assassin bugs molesting spiders in caves. And this time the observations were made in Minas Gerais, Brazil. One individual of the bug species Emesa mourei was seen standing on the web of a recluse spider (Loxosceles similis) while the spider was at the web’s edge. Another specimen of E. mourei was seen feeding on a fly near the web of a pholcid (cellar spider). The fly and the legs of the bug had vestiges of silk, indicating that the bug stole the fly from the spider. Another bug species, Phasmatocoris sp., was observed on a web of the cellar spider Mesabolivar aff. tandilicus. If this species of Phasmatocoris manipulates spider webs the same way that P. labyrinthicus seems to do is something yet to be investigated.

emesa_mourei_eating

Nymph of Emesa mourei feeding on a fly that it apparently stole from a pholcid spider in the cave Lapa Arco da Lapa, Minas Gerais, Brazil. Photo by Leonardo P. A. Resende, extracted from Resende et al., 2016.

With three different and very distant records of thread-legged assassin bugs associated with spiders in caves, it is clear that the poor arachnids cannot get rid of those bugs even if they run down into the bowels of the Earth.

– – –

ResearchBlogging.orgReferences:

PAPE, R. (2013). Description and Ecology of A New Cavernicolous, Arachnophilous Thread-legged Bug (Hemiptera: Reduviidae: Emesini) from Kartchner Caverns, Cochise County, Arizona Zootaxa, 3670 (2) DOI: 10.11646/zootaxa.3670.2.2

Resende, L., Zepon, T., Bichuette, M., Pape, R., & Gil-Santana, H. (2016). Associations between Emesinae heteropterans and spiders in limestone caves of Minas Gerais, southeastern Brazil Neotropical Biology and Conservation, 11 (3) DOI: 10.4013/nbc.2016.113.01

Wignall, A., & Taylor, P. (2010). Predatory behaviour of an araneophagic assassin bug Journal of Ethology, 28 (3), 437-445 DOI: 10.1007/s10164-009-0202-8

Wygodzinsky, P. W. 1966. A monograph of the Emesinae (Reduviidae, Hemiptera). Bulletin of the American Museum of Natural History, 133:1-614.

– – –

*Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommerical-NoDerivs 2.0 Generic License.

Leave a comment

Filed under Behavior, Conservation, Entomology, Spiders, Zoology

Friday Fellow: Sun Beetle

ResearchBlogging.orgby Piter Kehoma Boll

Who says beetles cannot be cute? Take a look at those guys:

pachnoda_marginata

They are eating a piece of banana. Photo by Wikimedia user Evanherk.*

These little fellows are beetles of the species Pachnoda marginata, commonly known as sun beetle or taxi cab beetle. Native from Africa, they reach up to 30 mm as adults and 60 mm as larvae and are one of the most common beetles raised as pets.

pachnoda_marginata_peregrina

An adult with the wings exposed, about to fly. Photo by Wikimedia user Drägüs.*

The sun beetle has nine subspecies, each with a particular color pattern. The most well known subspecies is Pachnoda marginata peregrina and is the one shown in the photos above.

Since the sun beetle is easy to keep in the lab, it has been eventually used in scientific studies, especially some related to the neurology of the olphactory receptors.

– – –

References:

Larsson, M. C., Stensmyr, M.. C., Bice, S. B., & Hansson, B. S. (2003). Attractiveness of Fruit and Flower Odorants Detected by Olfactory Receptor Neurons in the Fruit Chafer Pachnoda marginata Journal of Chemical Ecology, 29 (5), 1253-1268 DOI: 10.1023/A:1023893926038

Stensmyr, Marcus C., Larsson, Mattias C., Bice, Shannon, & Hansson, Bill S. (2001). Detection of fruit- and flower-emitted volatiles by olfactory receptor neurons in the polyphagous fruit chafer Pachnoda marginata (Coleoptera: Cetoniinae) Journal of Comparative Physiology A, 187 (7), 509-519

Wikipedia. Pachnoda marginata. Availabe at: < https://en.wikipedia.org/wiki/Pachnoda_marginata >. Access on September 8, 2016.

– – –

*Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

Leave a comment

Filed under Entomology, Friday Fellow, Zoology

Friday Fellow: Helicopter Damselfly

ResearchBlogging.orgby Piter Kehoma Boll

Damselflies are usually delicate versions of dragonflies, but some species challenge their place among the odonates. The most extreme example comes from the moist forests of Central and South America and is known as Megaloprepus caerulatus or the “helicopter damselfly”.

With a wingspan up to 19 cm, the helicopter damselfly is the largest of odonates and a voracious predator in both the aquatic naiad and the aerial adult forms.

megaloprepus_caerulatus

An adult female. Photo by Steven G. Johnson*

Female helicopter damselflies lay their eggs in water-filled tree hollows. Males are territorialists and defend the larger holes as territory, mating with females interested in laying eggs there.

The aquatic juvenile stage, known as naiad or nymph, is a top predator in this reduced ecosystem, feeding on mosquito larvae, tadoples and even other odonates. As adults, they feed mainly on web-building spiders that they capture in areas that receive direct sunlight, such as forest glades.

As the population size of the helicopter damselfly depends on the number and size of available tree hollows and considering that they avoid crossing large gaps between forest patches, any environmental disturbance may have profound impacts on this species. Recent molecular studies also suggest that what is known as Megaloprepus caerulatus is actually a complex of species, as there is no genetic flow between the populations. This makes it (or them) a much more vulnerable species.

– – –

References:

Feindt, W., Fincke, O., & Hadrys, H. (2013). Still a one species genus? Strong genetic diversification in the world’s largest living odonate, the Neotropical damselfly Megaloprepus caerulatus Conservation Genetics, 15 (2), 469-481 DOI: 10.1007/s10592-013-0554-z

Wikipedia. Megaloprepus caerulatus. Available at < https://en.wikipedia.org/wiki/Megaloprepus_caerulatus >. Access on September 7, 2016.

– – –

*Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

Leave a comment

Filed under Entomology, Friday Fellow, Zoology

Friday Fellow: Gold-and-Brown Rove Beetle

ResearchBlogging.orgby Piter Kehoma Boll

It’s time for our next beetle. Today the fellow I chose is Ontholestes cingulatus or gold-and-brown rove beetle. Rove beetles are the second most numerous family of beetles after weevils. Their more remarkable feature is that their elythra are short, not covering the abdomen most of the time. I always say that they look like if they were wearing a little jacket. So if you find an elongate beetle with short jacket-like elythra, it is most likely a rove beetle.

The gold-and-brown rove beetle is found throughout North America and is a predator as most rove beetles. It is usually found near carrion and dung, but it is not a scavenger. What it does there is too prey on fly larvae feeding on the rotten material.

An adult showing the nice golden "tail". Photo by Bruce Marlin.*

An adult showing the nice golden “tail”. Photo by Bruce Marlin.*

The gold-and-brown rove beetle is 13–20 mm long and mostly brown, but the last abdominal segments, as well as the underside of the thorax, have a beautiful and shiny gold color.

The mating behavior of the gold-and-brown rove beetle is interesting. Usually the male stays around the female after copulating with her in order to guard her from other males. This behavior usually ends soon after the female has laid the eggs, since at this point the male can be sure that he is the father of the children. To perform this guarding behavior is costly for the male, as he could be using this time to copulate with another female. But as receptive females are kind of rare, it is more advantageous to assure the paternity of the offspring of at least one female than to risk losing everything.

– – –

References:

Alcock, J. (1991). Adaptive mate-guarding by males of Ontholestes cingulatus (Coleoptera: Staphylinidae) Journal of Insect Behavior, 4 (6), 763-771 DOI: 10.1007/BF01052230

BugGuide. Species Ontholestes cingulatus – Gold-and-Brown Rove Beetle. Available at: < http://bugguide.net/node/view/9548 >. Access on August 1, 2016.

– – –

Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

Leave a comment

Filed under Behavior, Entomology, Friday Fellow, Zoology

Friday Fellow: Six-Spot Burnet

ResearchBlogging.orgby Piter Kehoma Boll

Found in Europe, today’s Friday Fellow is a nice day-flying moth with beautiful colors and toxic compounds. Scientifically known as Zygaena filipendulae, its common name is six-spot burnet, burnet being the common name of moths in the genus Zygaena and six-spot referring to the six red spots in each of the front wings. Those spots contrast beautifully with the dark blue or green metalic background of the wings, giving it some sort of mystical look, don’t you think?

The color say "I'm not edible". Photo by Vlad Proklov.*

The colors say “I’m not edible”. Photo by Vlad Proklov.*

As a caterpillar, the six-spot burnet feeds on leguminous plants, especially trefoils, and has a very different appearance, as usually in lepidopterans. It is yellow to greenish-yellow and has two rows of black spots running on the dorsum.

A chubby yellow caterpillar. Photo by Harald Süpfle.**

A chubby yellow caterpillar. Photo by Harald Süpfle.**

The plants used as food by the caterpillar contain cyanogenic glucosides, substances that are stored individually and produce toxic hydrogen cyanide when in contact with each other. This is used as a defense mechanism by the plant, but the caterpillar ingests and stores such compounds to use for its own defense. It has also been shown that the caterpillar is able to produce these cyanogenic glucosides by itself, thus not relying solely on the portion ingested with the food. Most of the compounds, however, are lost during the metamorphosis, so that the adults are much less toxic than the caterpillars.

– – –

References:

Zagrobelny, M., Bak, S., Olsen, C., & Møller, B. (2007). Intimate roles for cyanogenic glucosides in the life cycle of Zygaena filipendulae (Lepidoptera, Zygaenidae) Insect Biochemistry and Molecular Biology, 37 (11), 1189-1197 DOI: 10.1016/j.ibmb.2007.07.008

Wikipedia. Six-spot burnet. Available at: < https://en.wikipedia.org/wiki/Six-spot_burnet >. Access on August 1, 2016.

– – –

*Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Generic License.

**Creative Commons License
This work is licensed under a Creative Commons Attribution 2.5 Generic License.

Leave a comment

Filed under Entomology, Friday Fellow, Zoology

Friday Fellow: Jataí Bee

ResearchBlogging.orgby Piter Kehoma Boll

Certainly the most widespread, adaptable and well-known honey-producing bee is Apis melifera, commonly known as honeybee for obvious reasons. But there are a lot of other honey makers all over the world. Today I’m going to present you the most popular native bee in South America, Tetragonisca angustula, commonly known as jataí in Brazil and yateí, angelita, mariola and many other names in the Spanish-speaking countries.

Jataí bees at the entrance of their hive. Photo by Bernard Dupont.*

Jataí bees at the entrance of their hive. Photo by Bernard Dupont.*

Found from southern Mexico to southern Brazil and northern Argentina, the jataí bee is a very small stingless bee that easily thrives in urban areas. Measuring about 4–5 mm,  they build their nests in natural cavities of trees and sometimes in abandoned ant and termite nests or even in walls of human constructions.

Because it is a native species in the Neotropics, and therefore an important pollinator agent, and because it lacks a sting, being thus harmless to humans and domestic animals, the Jataí bee is an attractive species for domestication. In fact, the jataí bee is the only native stingless bee with a considerable large community of beekeepers maintaining hives. As the hives are small and harmless, they can also be used as effective pollinators of some plants, such as strawberries, inside greenhouses.

An individual jataí. Photo by George Shepherd.**

An individual jataí. Photo by George Shepherd.**

Considered of high quality, the honey produced by jataí bees is more expensive than that of common honeybees. In some places the price of jataí honey may be as much as ten times the price of honey produced by common honeybees. Just as the honey and propolis of common honeybees, jataí honey and propolis have antibacterial acitivity. People from communities in which the consuption of jataí honey is a common practice believe that it has medicinal properties, but actually there is no scientific evidence that jataí honey differs from the honey of common honeybees regarding this aspect.

– – –

References:

Malagodi-Braga, K. S., Kleinert, A. M. P. (2004). Could Tetragonisca angustula Latreille (Apinae, Meliponinni) be effective as strawberry pollinator in greenhouses? Australian Journal of Agricultural Research, 55 (7), 771-774. DOI: 10.1071/AR03240

Miorin, P., Levy Junior, N., Custodio, A., Bretz, W., & Marcucci, M. (2003). Antibacterial activity of honey and propolis from Apis mellifera and Tetragonisca angustula against Staphylococcus aureus. Journal of Applied Microbiology, 95 (5), 913-920 DOI: 10.1046/j.1365-2672.2003.02050.x

Sawaya, A., Cunha, I., Marcucci, M., de Oliveira Rodrigues, R., & Eberlin, M. (2006). Brazilian Propolis of Tetragonisca angustula and Apis mellifera. Apidologie, 37 (3), 398-407 DOI: 10.1051/apido:2006011

Wikipedia. Tetragonisca angustula. Available at: < https://en.wikipedia.org/wiki/Tetragonisca_angustula >. Access on August 1, 2016.

– – –

*Creative Commons License
This work is licensed under a Creative Commons Attribution 2.0 Generic License.

**Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Generic License.

Leave a comment

Filed under Entomology, Friday Fellow, Zoology