Why Locusts Would be Hawks

“War, huh, yeah
What is it good for?
Absolutely nothing.”
Edwin Starr

It’s arguable that things aren’t as clear cut as Starr’s 1969 hit makes out – that in fact, it all depends on perspective. Take locusts for example: if they were able to have a perspective, they’d be inclined to see the positive side of military might and political strife.

Locusts have a tendency to thrive where chaos reigns. War is good for going biblical, and in complex modern conflicts, they could often be considered the only winners. The problem with them taking their spoils of war, from an admittedly anthropocentric point of view, is that they’re spoiling often already-strained lives along the way.

It is a tragic truth that some of the world’s poorest – and most politically unstable – countries fall in the heart of the age-old battle against the family Acrididae’s most notorious member.

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Photo: Christiaan Kooyman/ Wikimedia Commons

Before we get into that, a slight clarification: locusts have very little in the way of hawkish tendencies when they’re on their own – they’re just solitary grasshoppers getting on with their lives. The problem is that they are the ultimate example of individuals which change their character in a group. When coming into close contact, for example in vegetation flushes after a drought, over a few generations, solitary becomes gregarious behaviour – and then comes potential trouble. War offers the chance to increase population density while no-one’s watching on. If caught too late, potentially catastrophic progress could be only at the whim of the wind.

At worst, locust swarms can reach hundreds of square miles in size, and travel vast distances. With each eating its weight in plants a day, the potential consequences are not hard to grasp.

But all is not lost. The fight to curtail locust upsurges brings out a gregarious side to entomologists, too. The field is often seen by outsiders as hermetic – but controlling locust populations is the definition of applied entomology, gone geopolitical and by its very nature, public.

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Photo: ©FAO/Giulio Napolitano. Editorial use only. Copyright FAO.

Annie Monard has been at the forefront of the human-locust struggle for over two decades at the Food and Agriculture Organization of the United Nations (FAO). For her team, tackling the desert locust (Schistocerca gregaria) in particular, is a never-ending and sometimes perilous mission.

“We balance the situation in a country when there are conflicts or instability,” says Monard. “We use information we can get in the neighbouring countries because what always has to be present in mind is that locusts are a trans-boundary pest. Generally, when there are locust issues, it is immediately in three, four countries.”

FAO has three Commmissions to cover S. gregaria’s huge distribution area. One of the three covers West and Northwest Africa – a region which includes Libya and Mali, two countries with current active conflict.

Mali is one of four countries in the region with permanent S. gregaria breeding populations. With access to the northern part of the country currently impossible, monitoring relies entirely on reports from locals and retired staff living in that area. These can be delayed or incomplete, but it’s something. At the same time, surveys have been intensified in bordering areas of neighbouring countries.

Instability can breed a pragmatic sort of creativity, and it is in evidence here. Soldiers in the national military have been given basic training to report on locust sightings, giving some added, combat-style ‘boots on the ground’ to the intelligence-gathering effort.

But there is conflict and there is conflict – and Yemen currently represents the gravest end of the spectrum. “Forget everything,” says Monard. “The same message is coming back: no surveys were carried out due to insecurity. So I mean, there is nothing. It is not possible to do the basic work in that country.”

When upheaval comes, agricultural budgets are often the first raided – as was the case during Madagascar’s military coup in 2009. Monitoring stopped, locusts bred unwatched, and populations surged quickly.

In frontline countries – those with permanent locust habitats and breeding areas – the aim is to survey as thoroughly as possible, aided by technology such as satellite imaging, drones and the FAO’s elocust system, which allows national field staff to input standardised data. If locusts would have a preference for states of war, the human counterinsurgency effort is becoming increasingly sophisticated.

Timing is everything in this war-within-wars. There’s no use trying to wipe out every locust, so you have to know when there’s enough massing to justify a strike. “We advocate a locust preventive control strategy relying on monitoring, early warning and early reaction,” added Monard. “Our aim is to try and be as proactive as possible – not acting as ‘firemen’.”

Though this human Vs. insect struggle offers no prospect of a definitive winner, and containment the only realistic prospect, rarely has entomology been so vital.

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On Insect cocks

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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.

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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.

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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.

 

Spiders and insects: Evolution’s Tom and Jerry chase?

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Among the many interesting points raised during our recent Diversity and Evolution of Insects module was the idea that spiders and insects may have been involved in a sort of cat and mouse pursuit through the fossil record.

It’s certainly the conclusion David Penney reached in his 2004 paper looking at insect and spider family diversity over geological time. It’s suggested here that the rate of exponential increase in diversity was the same for both groups, and that one’s line of rapid diversification – known as radiation – followed the other.

Both insects and spiders tend to be linked with the history of flowering plants, but interestingly, the study also suggests that the major radiations of both these classic antagonists were out of the way a good 100million years before the flora joined the party. This being the case, the arms race began without the need for the habitats that we’d probably associate with the modern tussle of flying insects and web-weavers.

Co-evolution has been proven to be more likely when there’s a direct interaction between groups, and at least one dependency, so the idea of a hunger so profound it transcended the ages certainly sounds plausible. Yet it’s not a view universally shared.

It’s hard to conceive of the struggle between insects and spiders without thinking of webs – and the diversity of arachnid species is linked with the diversity of web design. But in the poetically-titled Tangled in a sparse spider web, researchers at the University of Barcelona muddy the waters of the ‘insects lead, spiders follow’ story of speciation.

They make a case that the diversification of spiders and their web-building approaches was all about moving to different habitats and making use of food resources in an increasingly structurally complex world. To be clear, it’s abundance of prey, they say, that was more significant in driving a species-defining approach to webs rather than its diversity. Loads of flying insects, yes, but not necessarily loads of different ones. They also make the case that the explosion of orb-webs couldn’t have happened at the same time as the insects were on their fiercest period of diversification.

Searching for trends through what remains of the species that have been here and gone is a notoriously tricky business – something that is more than acknowledged by the authors of the different theories offered here. Missing data is one of the foremost problems with scouring the past for clues that may illustrate a trend, while the ‘family trees’ considered in invertebrate evolutionary studies are often complicated and controversial; subject to different interpretations and revisions.

So, has predator chased prey through the ages, or are things a little more complex than that? Well, this is science – never the easiest place to get a neat narrative from. So while you can find shadows of Tom and Jerry, Road Runner and Wile E. Coyote, Bugs and Elmer and the rest if you trace the lineages of Arachnida and Insecta, pinning evolutionary trends on a hunter-hunted analogy alone probably won’t quite cut it.

Meet the new ento-blogging team

New year, new team of aspirant entomologists writing for Mastering Entomology – and this time around there’s four of us. With no further ado, let’s introduce the team…

Ant lion

Here’s an antlion Sam found earlier

The antlion fanatic

Hey, I’m Sam. I’m actually a fairly recent convert to the ento crowd. My undergrad was in zoology, where I was considering going into conservation or behavioural research. As the leader of the course was an entomologist I did learn a lot about insects, but my passion wasn’t really ignited until a trip to Africa in my final year. In a place where monkeys and hippos are the norm, I found greater fascination in the intricate pitfall traps formed by the antlions that surrounded our hostel. That trip cemented in me a desire to understand the behaviour of insects and its evolution. Which is exactly why I’m here at Harper Adams. I’ll try my best to share all the interesting behaviours that I come across in my studies.

The future curator

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…and a death’s head hawkmoth Dom photographed earlier

Hi, I’m Dominic. I chose to study Entomology as I am very passionate about the subject and want to improve my knowledge and understanding of Insects. Ultimately, I wish to work as an Entomological curator where I can look after the important collections held within museums, educate the public on insects and hopefully conduct my own research to help the conservation of entomofauna and the habitats they reside in. My main interests in Entomology are Lepidoptera and Coleoptera (predominantly Moths and Scarabaeidae). I am fascinated with the way that Insects interact with and influence other organisms as well as looking at their roles in various ecosystems, I am also intrigued with how Insects have impacted human culture. In this blog I hope to write about insect behaviour, interactions, historical importance, environmental impacts and any other Entomology facts I find interesting.

 

Entomologists on wrekin

Gary (L) on a collecting mission with fellow members of the Harper ento crowd

The outlier

I’m Gary. You could certainly argue that I’m not the typical Entomology MSc student, having spent the last decade-plus in writing, communications and journalism. The love of insects has always been there, mind – just, it’s fair to say, lying somewhat dormant for a spell. Heavily influencing my taking of this somewhat tangential turn was time spent in the Prespa National Park in Greece, Albania and the Republic of Macedonia, where, similarly to Sam, I spent much of my time staring in awe at the biodiversity on the floor rather than looking out for bears, wolves or the magnificent array of bird species. Though I’m not exactly relishing the statistics that are to come as we work towards our final research projects, an insect-collecting trip up the Wrekin last week with some of my fellow Ento postgrads firmly fixed in my mind that I’ve made the right, albeit slightly curious, decision. Twitter: @garyfromleeds

Niahs aphid

Niah’s pet aphid mama

The pest patroller

Hi, I’m Niah, the token Integrated Pest Management student on this blog. I come from a science background, having just completed my Bachelor’s in Biological Science, but I knew next to nothing about entomology until my interest was sparked on a placement at the Warwick Crop Centre. Having spent a summer emptying traps, carrying out pesticide trials, and compiling citizen science moth counts into a report, I decided that pest management was the way forward! As well as singing the praises of biological control, I am especially interested in social insects, months, vectors of human disease and, of course, aphids. It’s quite a mixed bag but I’m looking forward to including some of them in this blog!

We’re aspiring to bring you some blog content that’s as diverse and intriguing as the world of our favourite arthropods. If we can get even remotely near, we’ll have done a pretty good job.