Tag Archives: Dictyoptera

Shocking News – the truth about electroperception – insects can ‘feel’ electric fields

Static electric fields are common throughout the environment and this has been known for some time (e.g Lund (1929) and back in 1918, the great Jean-Henri Fabre, writing about the dung beetle, Geotrupes stated “They seem to be influenced above all by the electric tension of the atmosphere. On hot and sultry evenings, when a storm is brewing, I see them moving about even more than usual. The morrow is always marked by violent claps of thunder

Given this, it is surprising that it was not until the 1960s that entomologists started to take a real interest in electroperception, when a Canadian entomologist decided to investigate the phenomenon further, but using flies (Edwards, 1960).  He found that if Drosophila melanogaster and Calliphora vicina exposed to, but not in contact with, an electrical field, they stopped moving. Calliphora vicina needed a stronger voltage to elicit a response than D. melanogaster, which perhaps could be related to their relative sizes. It seemed that their movement was reduced when electrical charge applied and changed, but not if the field was constant.

Responses of two fly species to electrical fields (From Edwards, 1960)

In a follow up experiment with the the Geometrid moth Nepytia phantasmaria he showed that females were less likely to lay eggs when exposed to electrical fields (Edwards, 1961), but the replication was very low and the conditions under which the experiment was run were not very realistic.

In the same year, Maw (1961) working on the Ichneumonid wasp, Itoplectis conquisitor, which is attracted to light, put ten females into a chamber with a light at one end but with parts of the floor charged at different levels.  The poor wasps were strongly attracted to the light but the electrical ‘barrier’ slowed them down; the stronger the charge, the greater the reluctance to enter the field.

On the other hand, some years later, working with the housefly, Musca domestica and the cabbage looper, Trichoplusia ni, across a range of different strength electrical fields, Perumpral et al., (1978)   found no consistent avoidance patterns in where the houseflies preferred to settle, but did find that wing beat frequency of male looper moths was significantly affected, although inconsistently.  Female moths on the other hand were not significantly affected.  This put paid to their intention to develop a non-chemical control method for these two pests.

A more promising results was obtained using the cockroach Periplaneta americana.  Christopher Jackson and colleagues at Southampton University showed that the cockroaches turned away, or were repulsed, when they encountered an electric field and if continuously exposed to one, walked more slowly, turned more often and covered less distance (Jackson et al., 2011).  As an aside, this is similar to the effects one of my PhD students found when she exposed carabid beetles exposed to sub-lethal applications of the insecticide dimethoate*.

Periplaneta americana definitely showing a reluctance to cross an electrical field (Jackson et al., 2011).

Other insect orders have also been shown to respond to electric fields.  Ants, in particular the fire ant, Solenopsis invicta, are apparently a well-known hazard to electrical fittings (MacKay et al., 1992), and a number of species have been found in telephone receivers (Eagleson, 1940), light fittings and switches (Little, 1984), and even televisions (Jolivet, 1986), causing short circuits and presumably, coming to untimely ends 🙂

Rosanna Wijenberg and colleagues at Simon Fraser University in Canada, really went to town and tested the responses of a variety of different insect pests to electric fields. They found that the common earwig, Forficula auricularia, two cockroaches, Blatta germanica, Supella longipalpa, two Thysanurans, the silverfish, Lepisma saccharina and the firebrat Thermobia domestica were attracted to, or at least arrested by electrified coils.  Periplaneta americana, on the other hand, was repulsed (Wijenberg et al., 2013).  They suggested that using electrified coils as non-toxic baits might be an environmentally friendly method of domestic pest control.  I have, however, not been able to find any commercial applications of this idea although perhaps you know better?

Although a number of marine vertebrates generate electricity and electric fields as well as perceiving and communicate using them, there was, until fairly recently, no evidence of electrocommunication within the insect world (Bullock, 1999); after all, they have pheromones 😊

When we look at the interaction between insects and electromagnetic fields there is growing evidence that bees, or at least honey bees, like some birds (Mouritsen et al., 2016) have the wherewithal and ability to navigate using magnetic fields (Lambinet et al., 2017ab).  Interestingly**, honeybees, Apis mellifera have been shown to generate their own electrical fields during their waggle dances which their conspecifics are able to detect (Greggers et al., 2013).  Bumble bees (Bombus terrestris), have also been shown to be able to detect electrical fields.  In this case, those surrounding individual plants.  The bees use the presence or absence of an electrical charge to ‘decide’ whether to visit flowers or not. If charged they are worth visiting, the charge being built up by visitation rates of other pollinating insects  (Clarke et al., 2013)

Since I’m on bees, I can’t leave this topic without mentioning mobile phones and electromagnetic radiation, although it really deserves an article of its own.  The almost ubiquitous presence of mobile phones has for a long time raised concern about the effect that their prolonged use and consequent exposure of their users to electromagnetic radiation in terms of cancer and other health issues (Simkó & Mattson, 2019). Although there is growing evidence that some forms of human cancer can be linked to their use (e.g. Mialon & Nesson, 2020), the overall picture is far from clear (Kim et al., 2016). Given the ways in which bees navigate and the concerns about honeybee populations it is not surprising that some people suggested that electromagnetic radiation as well as neonicitinoids might be responsible for the various ills affecting commercial bee hives (Sharma & Kumar, 2010, Favre, 2011). The evidence is far from convincing (Carreck, 2014) although a study from Greece looking at the intensity of electromagnetic radiation from mobile phone base stations on the abundance of pollinators found that the abundance of beetles, wasps and most hoverflies decreased with proximity to the base stations, but conversely, the abundance of bee-flies and underground nesting wild bees increased, while butterflies were unaffected (Lázaro et al., 2016). A more recent study has shown that exposure to mobile phones resulted in increased pupal mortality in honeybee queens but did not affect their mating success (Odemer & Odemer, 2019).  All in all, the general consensus is that although laboratory studies show that electromagnetic radiation can affect insect behaviour and reproduction the picture remains unclear and that there are few, if any field-based studies that provide reliable evidence one way or the other (Vanbergen et al., 2019).   Much more research is needed before we can truly quantify the likely impacts of electromagnetic radiation on pollinators and insects in general.

 

Acknowledgements

I must confess that I had never really thought about insect electroperception until I was at a conference and came across a poster on the subject by Matthew Wheelwright, then an MRes student at the University of Bristol, so it is only fair to dedicate this to him.

 

References

 

Bullock, T.H. (1999) The future of research on elctroreception and eclectrocommunicationJournal of Experimental Biology, 10, 1455-1458.

Carreck, N. (2014) Electromagnetic radiation and bees, again…, Bee World, 91, 101-102.

Clarke, D., Whitney, H., Sutton, G. & Robert, D. (2013) Detection and learning of floral electric fields by bumblebees. Science, 340, 66-69.

Eagleson, C. (1940) Fire ants causing damage to telephone equipment.  Journal of Economic  Entomology, 33, 700.

Edwards, D.K. (1960) Effects of artificially produced atmospheric electrical fields upon the activity of some adult Diptera.  Canadian Journal of Zoology, 38, 899-912.

Edwards, D.K. (1961) Influence of electrical field on pupation and oviposition in Nepytia phantasmaria Stykr. (Lepidoptera: Geometridae). Nature, 191, 976.

Fabre, J.H. (1918) The Sacred Beetle and Others. Dodd Mead & Co., New York.

Favre, D. (2011) Mobile phone induced honeybee worker piping. Apidologie, 42, 270-279.

Greggers, U., Koch, G., Schmidt, V., Durr, A., Floriou-Servou, A., Piepenbrock, D., Gopfert, M.C. & Menzel, R. (2013) Reception and learning of electric fields in bees. Proceedings of the Royal Society B, 280, 20130528.

Jackson, C.W., Hunt, E., Sjarkh, S. & Newland, P.L. (20111) Static electric fields modify the locomotory behaviour of cockroaches. Journal of Experimental Biology, 214, 2020-2026.

Jolivet, P. (1986) Les fourmis et la Television. L’Entomologiste, 42,321-323.

Kim, K.H., Kabir, E. & Jahan, S.A. (2016) The use of cell phone and insight into its potential human health impacts. Environmental Monitoring & Assessment, 188, 221.

Lambinet, V., Hayden, M.E., Reigel, C. & Gries, G. (2017a) Honeybees possess a polarity-sensitive magnetoreceptor. Journal of Comparative Physiology A, 203, 1029-1036.

Lambinet V, Hayden ME, Reigl K, Gomis S, Gries G. (2017b) Linking magnetite in the abdomen of honey bees to a magnetoreceptive function. Proceedings of the Royal Society, B., 284, 20162873.

Lazáro, A., Chroni, A., Tscheulin, T., Devalez, J., Matsoukas, C. & Petanidou, T. (2016) Electromagnetic radiation of mobile telecommunication antennas affects the abundance and composition of wild pollinators.  Journal of Insect Conservation, 20, 315-324.

Little, E.C. (1984) Ants in electric switches. New Zealand Entomologist, 8, 47.

Lund, E.J. (1929) Electrical polarity in the Douglas Fir. Publication of the Puget Sound Biological Station University of Washington, 7, 1-28.

MacKay, W.P., Majdi, S., Irving, J., Vinson, S.B. & Messer, C. (1992) Attraction of ants (Hymenoptera: Formicidae) to electric fields. Journal of the Kansas Entomological Society, 65, 39-43.

Maw, M.G. (1961) Behaviour of an insect on an electrically charged surface. Canadian Entomologist, 93, 391-393.

Mialon, H.M. & Nesson, E.T. (2020) The association between mobile phones and the risk of brain cancer mortality: a 25‐year cross‐country analysis. Contemporary Economic Policy, 38, 258-269.

Mouritsen, H., Heyers, D. & Güntürkün, O. (2016) The neural basis of long-distance navigation in birds. Annual Review of Physiology, 78, 33-154.

Odemer, R., & Odemer, F. (2019). Effects of radiofrequency electromagnetic radiation (RF-EMF) on honey bee queen development and mating success. Science of The Total Environment, 661, 553–562.

Perumpral, J.V., Earp, U.F. & Stanley, J.M. (1978) Effects of electrostatic field on locational preference of house flies and flight activities of cabbage loopers. Environmental Entomology, 7, 482-486.

Sharma, V.P. & Kumar, N.R. (2010) Changes in honeybee behaviour and biology under the influence of cellphone radiation. Current Science, 98, 1376-1378.

Simkó, M. & Mattson, M.O. (2019) 5G wireless communication and health effects—A pragmatic review based on available studies regarding 6 to 100 GHz. International Journal of Environmental Research & Public Health, 16, 3406.

Vanbergen, A.J., Potts, S.G., Vian, A., Malkemper, E.P., Young, J. & Tscheulin, T. (2019) Risk to pollinators from anthropogenic electro-magnetic radiation (EMR): Evidence and knowledge gaps. Science of the Total Environment, 695, 133833.

Wijenberg, R., Hayden, M.E., Takáca, S. & Gries, G. (2013) Behavioural responses of diverse insect groups to electric stimuli. Entomoloogia experimentalis et applicata, 147, 132-140.

 

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yet another entry for my data I am never going to publish series 😊

 

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My wife really hates it when I start a sentence like this, as she says “You’re always starting sentences like that and it is rarely interesting”

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Twisted, hairy, scaly, gnawed and pure – side-tracked by Orders

I’m supposed to be writing a book, well actually two, but you have to be in the right mood to make real progress. Right now, I’m avoiding working on one of the three chapters that I haven’t even started yet* and I really should be on top of them by now as I have already spent the advance, and have less than a year to go to deliver the manuscript 😦 Instead of starting a new chapter I’m tweaking Chapter 1, which includes an overview of Insect Orders.  While doing that I was side tracked by etymology. After all, the word is quite similar to my favourite subject and a lot of people confuse the two. Anyway, after some fun time with my Dictionary of Entomology, (which is much more of an encyclopaedia than a dictionary), and of course Google, I have great pleasure in presenting my one stop shop for those of you who wonder how insect orders got their names.  Here they are, all in one easy to access place with a few fun-filled facts to leaven the mixture.

Wings, beautiful wings (very much not to scale)

First, a little bit of entomological jargon for those not totally au fait with it.  Broadly speaking we are talking bastardised Greek and Latin. I hated Latin at school but once I really got into entomology I realised just how useful it is.  I didn’t do Greek though 😊, which is a shame as Pteron is Greek for wing and this is the root of the Latin ptera, which features all over the place in entomology.

Since I am really only talking about insects and wings, I won’t mention things like the Diplura, Thysanura and other Apterygota.  They don’t have wings, the clue being in the name, which is derived from Greek; A = not, pterygota, derived from the Greek ptérugos = winged, which put together gives us unwinged or wingless. In Entojargon, when we talk about wingless insects we use the term apterous, or if working with aphids, aptera (singular) or apterae (plural).   I’m going to deal with winged insects, the Exopterygota and the Endopterygota. The Exopterygota are insects whose wings develop outside the body and there is a gradual change from immature to adult.  Think of an aphid for example (and why not?); when the nymph (more Entojargon for immature hemimetabolus insects) reaches the third of fourth instar (Entojargon for different moulted stages), they look like they have shoulder pads; these are the wing buds, and the process of going from egg to adult in this way is called incomplete metamorphosis.

Fourth instar alatiform nymph of the Delphiniobium junackianum the Monkshood aphid.  Picture from the fantastic Influential Points site https://influentialpoints.com/Images/Delphiniobium_junackianum_fourth_instar_alate_img_6833ew.jpg (Any excuse for an aphid pciture)

In the Endopterygota, those insects where the wings develop inside the body, e.g butterflies and moths, the adult bears no resemblance to the larva and the process is described as complete metamorphosis and the life cycle type as holometabolous. It is also important to note that the p in A-, Ecto- and Endopterygota is silent.

Now on to the Orders and their names.  A handy tip is to remember is that aptera means no wings and ptera means with wings.  This can be a bit confusing as most of the Orders all look and sound as if they have wings.  This is in part, due to our appalling pronunciation of words; we tend to make the syllables fit our normal speech patterns which doesn’t necessarily mean breaking the words up in their correct component parts. Diptera and Coleoptera are two good examples – we pronounce the former as Dip-tera and informally as Dips.  From a purist’s point of view, we should be pronouncing the word Di-tera – two wings, and similarly, Coleoptera as Coleo-tera, without the p 🙂 Anyway, enough of the grammar lessons and on with the insects.

Exopterygota

Ephemeroptera The Mayflies, lasting a day or winged for a day J The oldest extant group with wings. They are also a bit weird, as unlike other Exopterygota they have a winged sub-adult stage

Odonata              Dragonflies and Damselflies – think dentists, toothed, derived from the Greek for tooth, odoús. Despite their amazing flight capability, the name refers to their toothed mandibles.  The wings do get a mention when we get down to infraorders, the dragonflies, Anisoptera meaning uneven in that the fore and hind wings are a different shape and the damselflies, Zygoptera  meaning even or yoke, both sets of wings being pretty much identical.

Dermaptera       Earwigs, leathery/skin/hide, referring to the fore-wings which as well as being leathery are reduced in size.  Despite this, the much larger membranous hind wings are safely folded away underneath them.

A not very well drawn (by me) earwig wing 😊

Plecoptera          Stoneflies, wickerwork wings – can you see them in the main image?

Orthoptera         Grasshoppers and crickets, straight wings, referring to the sclerotised forewings that cover the membranous, sometimes brightly coloured hind wings.  Many people are surprised the first time they see a grasshopper flying as they have been taken in by the hopper part of the name and the common portrayal of grasshoppers in cartoons and children’s literature; or perhaps not read their bible “And the locusts went up over all the land of Egypt, and rested in all the coasts of Egypt”. I think also that many people don’t realise that locusts are grasshoppers per se.

Grasshopper wings

Dictyoptera        Cockroaches, termites and allies, net wings

Notoptera           The order to which the wingless Ice crawlers (Grylloblattodea) and Gladiators Mantophasmatodea) belong. Despite being wingless, Notoptera translates as back wings. It makes more sense when you realise that the name was coined when only extinct members of this order were known and they were winged.

Mantodea           Mantids, the praying mantis being the one we are all familiar with, hence the name which can be translated as prophet or soothsayer

Phasmotodea    Phasmids, the stick insects and leaf insects – phantom, presumably referring to their ability to blend into the background.

Psocoptera         Bark lice and book lice, gnawed or biting with wings. In this case the adjective is not in reference to the appearance of the wings, but that they are winged insects that can bite and that includes humans, although in my experience, not very painful, just a little itchy. They are also able to take up water directly from the atmosphere which means that they can exploit extremely dry environments.

Embioptera        Web spinners, lively wings. Did you know that Janice Edgerly-Rooks at Santa Clara University has collaborated with musicians to produce a music video of Embiopteran silk spinning? https://www.youtube.com/watch?v=veehbMKjMgw

Zoraptera            Now this is the opposite of the Notoptera, the Angel insects, Zora meaning pure in the sense of not having any wings.  Unfortunately for the taxonomists who named this order, winged forms have now been found 🙂

Thysanoptera    Thrips and yes that is both the plural and singular, thysan meaning tassel wings, although I always think that feather would be a much more appropriate description.

Feathery thrips wing – Photo courtesy of Tom Pope @Ipm_Tom

Hemiptera          True bugs – half wings.  The two former official suborders were very useful descriptions, Homoptera, e.g. aphids, the same. Heteroptera such as Lygaeids, e.g. Chinch bugs, which are often misidentified by non-entomologists as beetles where the prefix Hetero means different, referring to the fact that the fore wings are hardened and often brightly coloured in comparison with the membranous hind wings.

Coreid bug – Gonecerus acuteangulatus – Photo Tristan Banstock https://www.britishbugs.org.uk/heteroptera/Coreidae/gonocerus_acuteangulatus.html

Phthiraptera      The lice, the name translates as wingless louse. I guess as one of the common names for aphids is plant lice they felt the need to make the distinction in the name.

Siphonaptera     Fleas – tube without wings, referring to their mouthparts

 

Endopterygota

Rhapidioptera   Snakeflies – needle with wings, in this case referring to the ovipositor, not to the wings, which are similar to those of dragonflies.

The pointy end of a female snakefly

Megaloptera      Alderflies, Dobsonflies – large wings

Neuroptera        Lacewings – veined wings

Coleoptera         Beetles – sheathed wings, referring to the hardened forewings, elytra, that cover the membranous hind wings. The complex process of unfolding and refolding their hind wings means that many beetles are ‘reluctant’ to fly unless they really need to.

Strepsiptera       These are sometimes referred to as Stylops.  They are endoparasites of other insects. The name translates as twisted wings. Like flies, they have only two pairs of functional wings the other pair being modified into halteres.  Unlike flies, their halteres are modified fore wings.  Their other claim to fame is that they feature on the logo of the Royal Entomological Society.

The Royal Entomological Society Strepsipteran

Mecoptera         Scorpionflies, hanging flies – long wings.  Again, not all Mecoptera are winged, but those that are, do indeed have long wings in relation to their body size.

Male Scorpionfly, Panorpa communis.  Photo David Nicholls https://www.naturespot.org.uk/species/scorpion-fly

Siphonaptera     Fleas – tube no wings. The tube part of the name refers to their mouthparts.

Diptera                 Flies, two wings, the hind pair are reduced to form the halteres, which are a highly complex orientation and balancing device.

Trichoptera         Caddisflies, which are, evolutionarily speaking, very closely related to the Lepidoptera.  Instead of scales, however, their wings are densely cover with small hairs, hence the name hairy wings.  Some species can, at first glance, be mistaken for small moths. If you want to know more about caddisflies I have written about them here.

Lepidoptera       Moths and butterflies, scaly wings; you all know what happens if you pick a moth or butterfly up by its wings.

Moth wing with displaced scales

 

Hymenoptera    Wasps, bees, ants – membrane wings

Wing of a wood wasp, Sirex noctilio

 

And there you have it, all 30 extant insect orders in one easy location.

 

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Cockroach – an unlikely pairing

Cockroaches, like aphids, tend to get a bad press, the former as objects of disgust, the latter as pests. This is of course because our perception of cockroaches is heavily influenced by the scuttling, slithering and susurrus images that haunt our memories from watching too many reality TV shows and horror films*.

Cockroaches are members of the superorder, Dictyoptera and are placed in the order Blattodea, (derived from the Latin, blatta, an insect that shuns light) which, perhaps somewhat surprisingly, along with the termites (inward et al., 2007).  When I was a student termites had their own Order, Isoptera; molecular biology and DNA studies have a lot to answer for 🙂  There are currently, about 4,600 described species, of which thirty are associated with humans and a mere four which are considered to be pests (Bell et al., 2007); see what I mean about a bad press.  They have a global distribution but are mainly associated with the tropics and sub-tropics.

According to the Oxford English Dictionary (and whom am I to doubt them?), the name “cockroach” comes from the Spanish word cucaracha, transformed by 1620s English folk etymology (where an unfamiliar word is changed into something more familiar) into “cock” (male bird) and “roach” (a freshwater fish).  I find this a little odd.  Given that the Romans were trading globally before they colonised England, it seems unbelievable that the Oriental and German cockroaches would not have made it to the British Isles and become a familiar pest, before the early seventeenth century.  That said, Robinson (1870) suggests that according to Gilbert White the Oriental cockroach Periplaneta orientalis, sometimes called the black beetle (e.g. Blatchley, 1892), was not introduced into England until 1790.  A reference in Packham (2015) however puts its introduction as 1644, which fits better with the OED’s date of derivation of the word.  I would, despite this, still suggest that the Romans would have been the more likely ones to have brought it to our shores.  I think it quite likely that anything that scuttled along the ground and was dark in colour would have been referred to as a black beetle, so my view is that our pestiferous cockroaches have been around much longer.  Any sources to prove/disprove this will be welcome.

Our native cockroaches, as opposed to those that have become naturalised, are shy, retiring, quite rare and located mainly in the south of England, where they dwell peacefully among the trees and heather, a situation that has remained largely unchanged for almost 200 years (Stephens, 1835).  Their names, except for Ectobius pallidus, seem to indicate an origin from farther afield, or perhaps just reflect the origin of the entomologist who first described them  🙂

Ectobius panzeri, The Lesser cockroach (distribution from the NBN Atlas)

Ectobius lapponicus, The Dusky cockroach (Distribution from the NBN Atlas). It is also known as the Forest cockroach in Hungarian   http://regithink.transindex.ro/?p=8782.  According the NBN Atlas it has been recorded as eating aphids.

Ectobius lapponicus showing the wings unfolded.

Ectobius pallidus, the Tawny cockroach (also known as Mediterranean Spotted Cockroach) (Distribution from the NBN Atlas)

 

Cockroaches, unlike ladybirds and aphids, don’t seem to have amassed a huge number of weird and wonderful names in other languages.  If anyone has some good examples to add, please let me know.

Albanian kakabu

Basque labezomorro (labe = oven, zomorro = bug)

Bulgarian хлебарка khlebarka

Finnish torakka

French  cafard (in English melancholia)

German kakerlake

Hungarian csótány

Italian scarafaggio (sounds like a character from an Opera)

Latin blatta

Latvian prusaku

Polish karaluch

Spanish cucaracha

Swedish kackerlacka

Yiddish tarakan

In terms of aesthetically pleasing versions I found Armenian ծխամորճ and Thai แมลงสาบ the most satisfying, and Japanese definitely the most abrupt  ゴキブリ

And to end,  a fun fact that might make some of you disposed to look more kindly upon the cockroach “The Cockroach is the natural enemy of the bed-bug, and destroys large numbers” (Packard, 1876).

 

References

Bell, W.J., Roth, L.M. &  Nalepa,  A.A. (2007) Cockroaches: Ecology, Behavior and Natural History.  The Johns Hopkins University Press, Baltimore.

Blatchley, W.S. (1892) The Blattidae of Indiana.  Proceedings of the Indiana Academy of Science, 1892, 153-165.

Brown, V.K. (1980)  Notes and a key to the Oothecae of the British Ectobius (Dictyoptera: Blattidae).  Entomologist’s Monthly Magazine, 116, 151-154.

Inward, D., Beccaloni, G. & Eggleton, P. (2007) Death of an order: a comprehensive molecular phylogenetic study confirms that termites are eusocial cockroaches. Biology Letters, 3, 331-335.

Packham, C. (2015) Chris Packham’s Wild Side of Town. Bloomsbury Press, London.

Packard, A.P. (1876) Guide to the Study of Insects and a Treatise on those Beneficial and Injurious to Crops. Henry Holt & Company, New York.

Robinson, C.J. (1870) The cockroach.  Nature, 2, 435.

Stephens, J.S. (1835) Illustrations of British Entomology; or a Synopsis of Indigenous Insects. Volume VI. Mandibulata.  Baldwin & Cradock, London.

 

 

 

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