On Insect cocks


Cock. Penis. Dick. Wang. Whatever you call the male appendage, this is an area of insect physiology where things get pretty wild. Or perhaps more accurately, wilder than the usual.

But let’s start scientifically-correct: in the insect world the closest thing to the human penis is more properly known as the aedeagus. But ‘closest thing’ does not in any way imply great similarity. It’s actually part of the insect abdomen, and the external part of the male’s sexual weaponry is a phallus of extremely various flaps, hairs and hooks. Still with this? Good.

When it comes to shape, describing the situation as complex doesn’t get anywhere near to doing it justice. Menno Schilthuizen’s account of genital evolution is a comprehensive overview (far more so than can be included here), highlighting a wonderfully alien world of ‘prongs’, ‘pegs’, ‘springs’ and ‘titillators’. If insects are purely in it for the passing of genes, they could’ve fooled us.

aphid cock 1

Amazing aphid dicks: from Wieczorek et al, 2011 

There’s so much to say about the morphology of aphid appendages alone that the main journal paper on the matter comes in two parts. For relatively small insects, aphids come with a significant package – “relatively large and discernible under a hand lens or even with the naked eye”. The paper includes such descriptive gems as “a few circular pits distributed mostly in its medial part. Sclerotized arms with distal part rather long and thin, and proximal part shorter and wider. Aedeagus long, inverted question mark-shaped.” And that’s just the aphid Drepanosiphumplatanoidis. Big name, big aedeagus.

Smutty jokes aside (but not for long), in insect taxonomy, male sexual organs can be extremely helpful in establishing exactly what species you’re dealing with. In fact, it can often be the only way of making a certain identification. So far, so useful, to us as well as them. But how do insects actually, you know, do it? Again, this is no simple matter.

dragonfly dicks - miller 1991

Normal for dragonflies: from Miller, 1991

The ‘lock and key hypothesis’ is an idea that has persisted in entomology – and, naturally,
argued over. It asserts that male and female sexual organs of an insect species, whatever wacky shape and size they are, have evolved to only be the exact ‘fit’ for each other. The theory, however, has been largely discredited over the years.

What’s abundantly clear is that sex is rarely anything straightforward in the insect world – there’s little by way of proxy for missionary. Dragonflies are a good go-to example for the messiness of it all – so much so that their sexual antics inspired a New York Times article, in which the slaty skimmer (Libellula incesta) is described as having a “fairly rococo penis”. Sex begins with what constitutes foreplay – the male grabbing the female at the back of the head – while dragonfly dongs are not just about depositing sperm, they’re also about removing that of rivals. Naturally, females are tooled up to stop that happening, if at all possible.


Brutal bruchid beetle bell-end: Wikimedia Commons

The mealworm beetle (Tenebrio molitor) also has a dick geared up to dispatch the genes of its rivals. In the words of this paper on the matter, it “comprises a central shaft enclosed within a flexible sheath covered with chitinous spines. As the shaft extends within the female’s copulatory bursa the sheath and its covering of spines rolls back producing a `scouring’ effect.” Lovely.

With schlongs often more resembling torture implements, things can get even more brutal. Males of the bruchid beetle (Callosobruchus maculatus) actually damage the female’s reproductive tract during sex, and females, understandably, kick them for it. If she doesn’t kick, injuries tend to be worse after a longer sex session. Yet according to this paper, the carnage is not a deliberate act of destruction by the males, just an unfortunate by-product of them evolving weapons that are literally weapons. Why, it’s not yet known, but the theory is its all about being able to cling tightly to their ‘loved’ one.

If this blog puts insects in danger of being adopted by the alt-right as beacons of ultra- masculinity, hold that thought right there. Transgression of gender norms is happening in Brazilian caves, don’t you know. In the louse genus Neotrogla, it’s the females with the penis-like protrusion, and the guys with a chamber comparable to a vagina. A very niche re-definition of ‘wearing the trousers’ for sure, and in marked contrast to the species of beetles and dragonflies using their phallus to screw over their rivals with a bit of sperm scooping, our ‘macho’ cave-based females are using theirs to collect it up. Through all the kink and horror, life finds a way.

So there, a piece about insect nobs has been published on the Entomology MSc blog. I can only hope this comes up in the exams in March, making things a little less hard. Too much smut? Probably.


An Update (Part 1)

It has been a hot minute since we posted the last article which introduced us, so a little update about what us budding entomologists have been getting up to on the course so far and my thoughts on it seemed rather apt. I present to you part one of the overview/highlights of what we’ve done so far:

Module 1: Biology & Taxonomy of Insects

Following the introductory Research & Information Skills module, this was the first entomology module with two weeks of entomological goodness for the cohort to get stuck into, and boy, we weren’t left disappointed. The module started with a session on Orthoptera and a general run through of insect anatomy led by Dr. Andy Cherrill. This was followed by practical session which involved a delightful dissection of the desert locust (Schistocerca gregaria).


The next day we covered the order Thysanoptera (thrips) with Dr Tom Pope (@ipm_tom), followed by a zoom through the superorder Dictyoptera (comprising of the orders Mantodea (mantids) and Blattodea (cockroaches and termites)) with Dr. Rob Graham. With everyone on the course being from varied backgrounds and holding different levels of experience within different things, the session on insect pinning and curation was extremely useful for everyone. The cohort spent the afternoon pinning, micropinning and carding insects in a thrilling practical session led by PhD student Francisca Sconce (@FranciscaSconce).


Pinned 3rd instar desert locust nymph and carabid (specimens pinned and photographed by Linzi (@Apis_linzi)).

After a whizz through a lecture on sampling methods by Prof. Simon Leather (@EntoProf) we covered a range of methods, ranging from beating to sweep netting and from pitfall traps to malaise traps. The afternoon was spent in the great outdoors sweep netting and getting to use the Vortistm, a vacuum used to suck up and sample insects (and relatives).


Fellow entomologist Brinna (@BrinnaBarlow) trying her hand at sampling some insects using the Vortis suction sampler.

The first week of this module ended with a bang, with the first guest speaker from the Natural History Museum: hymenopterist Dr. Andy Polaszek (@AndyPolaszek)! In a blitz through the hyper diverse Hymenoptera, we covered several groups, focusing on their identification as well as some tidbits on their biology. We put what we learnt during the morning lecture to test in an intense identification practical.




Week two of the module started with an aphid-packed day on Hemiptera. The next day was Lepidoptera-filled. We had a practical session which involved taking morphometric measurments in waxmoths (Galleria mellonella) and dissecting out the females ovarioles to count the number of eggs.


A female wax moth (Galleria mellonella) dissected with ovarioles spread out, as part of the Lepidoptera class practical.

Speaker number two from NHM was THE fly girl herself, Dr. Erica McAllister (@flygirlNHM)! She vividly captured our interest and introduced us to the weird and wonderful world of flies. Leading on nicely from the zoom through Diptera, we had a session on Forensic Entomology, full of murder (not literally of course…that’d be bad) and maggots with one of the UK’s leading forensic entomologist’s Dr. Amoret Whitaker. The module ended with shimmer and shine a.k.a beetles, with coleopterist Dr. Max Barclay (@Coleopterist)!


This module was certainly a personal favourite of mine (so far), we covered SOOO MUCH in a relatively short space of time. With informative lectures from the university lecturers, plenty of hands on practicals, combined with several external speakers who are experts within their respective fields; I feel as though we thoroughly covered the major insect orders in a very engaging manner! A truly fantastic start to the course!

Make sure to check out the next post “An Update (Part 2)” on Saturday!


By Aqib Ali  (Twitter:@EntoAqib , Email: Aqib1996@hotmail.co.uk , Linkedin: Aqib Ali)

MSc Entomology Twitter: @EntoMasters

Parenting for Dummies (feat. burying beetles)

Festive greetings readership,

On a gloomy, mist-filled night, the life of a mouse is gently extinguished by disease. Its blood stills, its body cools, and a slight wind carries its almost imperceptible scent through the air. A faint buzzing approaches from the darkness, growing louder and louder; a flash of jet-black and red in the moonlight. Another. Then… silence. Two beetles scamper onto the carcass after their nightly flights. They are burying beetles, a male and a female, and have much to do over the next 2-3 weeks. Continue reading

Who’s said it’s all over after death? Power to the rot!

Imagine you’ve baked a cake but it didn’t turn out as you planned. The nearest shop is 1.5h away and the cake needs to be ready within 4h. You’ve got no time to replace the ingredients and also bake another cake. Fortunately, you can separate all the ingredients used and start again. The decomposition process does just that.

What’s decomposition? You may ask. Well, is the process where animal, plant, fungi or any other organism’s matter breaks down. It’s all natural, with no frills attached, and releases essential nutrients back into the ecosystem. Great part of this process is carried out by our beloved insects with a little help from their symbiotic friends. All organisms on Earth will come to a point when they die. Luckily we can’t live forever and this realisation is reassuring.

Carrion (dead animals) left on ground surface will soon be visited by insects. Blow-flies (Calliphoridae) and Flesh-flies (Sarcophagidae) will first appear to lay their eggs. The hatched grubs (larvae) will feed furiously as if bound by a time constrain. Quite right they are. There’s loads of competition for such a valuable resource. Hide beetles (Dermestes maculatus De Geer, 1774) first appear after a few days or weeks. Although, often considered a pest of dry meats, it provides valuable services to humans. It can deliver an estimated post-mortem interval or be used in skeleton preparations. Ants (Hymenoptera) might not be your first though when it comes to carrion but they also play their part. It could be by direct feeding or emission of odours which signals to other insects the presence of a food source. On a different scale, Mayfly larvae (Ephemeroptera) and Caddisfly larvae (Trichoptera) play a role in the decomposition of submerged carrion.

Have you ever noticed Rose chafers (Cetonia aurata) adding extra beauty to your flowers and wonder where they keep their babies? The larvae might be busy at work breaking down your compost pit. Houseflies (Muscidae) can be a nuisance when you’re trying to eat al fresco. These fast flyers have a bigger interest in laying their eggs in carrion, leaf-litter or dung than in our food. Egg survival rates are unlikely once we ingest egg-fly contaminated food. Dung beetles (Scarabaeoidae) is another example of perfect beauty. Although, as all other insects, they aren’t just a pretty face. They collect mammals’ excreted waste and clean up our green areas.

Dead tree logs left in contact with soil will soon be a home for many insects. Contact with soil is important for maximal enzyme function. Enzymes are proteins produced by living organisms which accelerate a chemical process. Soil contact prevents logs from quickly drying out and makes them suitable for an array of insects. Thus, moisture is thoroughly important. Remember this next time you decide to help our saproxylic friends. You don’t need huge logs. Even wood chips left on top of plant pots filled with soil and wood chips will be better than nothing. You might be rewarded by a Stag beetle, Lesser stag beetle or Rhinoceros beetle peeping out ready for mating.

Through the process of wood decay, parasitoids could emerge and conquer. The slim waist of wasps has evolved in junction with the need of flexibility. Their need to direct the ovipositor (insect’s organ at the end of the female abdomen used to deposit eggs) into decaying wood. Subsequently, in some species, has evolved to egg laying directly into other insects. Wood wasps will pierce dead wood or weaken wood with their ovipositor. They will lay their eggs together with a self-carrying fungus. The Sabre wasp (a parasitoid) makes great use of their slim waist. They can detect Wood wasps’ larvae and lay their eggs into the larvae with great precision. Parasitoids are extremely important in agriculture. In many cases they can replace harmful pesticides.

Ambrosia beetles and Leafcutter ants realized that fungi were efficient at breaking down plant cell walls. Fungi can outcompete other organisms in the decomposition race. So, creating a long lasting relationship with fungi was a great idea. These insects have been cultivating crops for over 50 million years. The Ambrosia beetle will create a habitat for the fungus to flourish and in return has a continuous supply of food by feeding on the fungus itself. Leafcutter ants also feed on the fungus but supplies it with fresh leaves instead of self-build wood galleries. The insects will also make sure that the fungus remains in good health by associating with bacteria.

Sadly, many academic institutions are moving away from traditional fields. Expecting that a true understanding of the natural world is not required. We can’t forget the little things in life. They’ve been successful throughout evolution before we even thought of cooking. When the world was getting ready to welcome natural history the doors to the natural world were shut. Although, the eternal need to save humans is forcing human kind to look at insects again. Such as, better understanding in integrated pest management (IPM) to avoid pesticide resistance and reduce crop wastage or decomposition for novel antibiotics.

Author: Ana Natalio @EntoAim