Fear of Moths: Ridiculous or Reasonable?

Alright, confession time: one of my best friends is scared of moths. I know, it was a shock for me too. I found this out about two and a half years ago when I sent this friend (let’s call her Sarah because that is her name) pictures of a poplar hawk moth I’d caught. In hindsight, maybe I should have checked first.

Like all phobias, it can be really difficult for those of us without it to understand what the problem is so I asked Sarah exactly what she doesn’t like:

“I don’t like them cause they freak me out irl when they fly in my face and they’re fuzzy and look like death and just looking at them gives me shivers

That any good for your blog?”

Although we often refer to it as lepidopterophobia (the irrational fear of all Lepidoptera), its true form is actually very rare. Many people are terrified of moths but have no problem at all with butterflies, leading to mottephobia (the irrational fear of moths) being increasingly common.

cof

The picture that started it all.

 

Specific phobias” are an intense and persistent fear of a certain object or situation, most of which are thought to develop in childhood as a result of a traumatic experiences and/or genetic predisposition, and usually go away by adulthood. In the case of a lot of common fears, such as arachnophobia or cynophobia (fear of spiders and dogs, respectively), it is thought that they might be an evolutionary adaptation to things which were once dangerous for us, even if they aren’t any more. Both of these factors make sense for fears of things which can hurt you, bees and wasps for example, but what possible harm can moths do?

According to some sources, it seems Sarah is not alone, the fear is mostly linked to movement. Some find the unpredictable fluttering flight patterns unsettling, feeling uncomfortable when a butterfly or moth flies near them in case it lands on them or brushes against their skin. These fears are multiplied when the insects are swarming in groups, something which must make lepdiopterophobes who live in monarch butterfly migratory “highways” somewhat uncomfortable. At the end of the day, it seems to be the unpredictability which is especially fear-provoking, which ties in with the fear of the unknown. This still doesn’t answer why more people are scared of moths than butterflies and it doesn’t seem that clear. My best guess is that is has something to do with the fact that we mostly encounter moths by night as they try to get into our houses – a distinctly creepy scenario.

Although it is important to be understanding of people with true mottephobia, there is a greater issue here: that of irrational disgust and dislike of interests, without the excusable irrational fear and panic of a phobia. A third of fear of British animals in UK adults was of “fear-relevant animals” (snakes etc.) and invertebrates. Not of fear relevant invertebrates like wasps and bees, or even disease relevant invertebrates like mosquitos and cockroaches, just “invertebrates”. The paper even lists slugs and worms as given examples of feared invertebrates, suggesting that the disgust the great British public feels about “creepy crawlies” is entirely without logical reason.

To a certain extent it can be argued that fears develop because of a lack of exposure: students from urban areas on field trips to wildland areas were recorded as frequently expressing a fear and disgust of insects, as well as snakes, plants, and “getting lost”. Fear of the unknown is considered by some researchers to be “the fundamental fear”; what you don’t know can, in fact, hurt you. To link this back to mottephobia, if the only exposure you have to moths is them flapping in your face on summer evenings, I can see why it would be annoying, even distressing and how that could develop into a fully blown phobia.

flesh moth.jpg

Even by the BBC’s standards this was a weird one

The idea for this article was sparked by an episode of Doctor Who back in November where the Doctor and her companions ended up in an anti-zone between universes infested with flesh moths: enormous carnivorous moths which are attracted to light and movement and could strip the flesh from prey in moments. Look, don’t ask me, ask the BBC.In order to reduce and remove specific phobias, exposure therapy is used to gradually reduce the amount of fear associated with a trigger.  But how are people supposed to ‘grow out’ of their childhood fears if the media constantly feeds us negative images of insects?

Now whilst some moths do, as Sarah said, “look like death” (I’m looking at

death's head hawk moth.jpg

Acheronita atropos, the Death’s Head Hawk Moth with its distinctive skull-shaped marking

you, Death’s Head Hawk Moth), there are many more which are beautiful and play incredibly important roles in their ecosystems – one of the best well known being the obligate mutualism between yuccas and yucca moths. Maybe the fact we never see these moths represented in the media but are regularly exposed to butterflies in a positive context also contributes to the difference in attitudes.

atlas moth.jpg

The truly beautiful, and somewhat butterfly-like, atlas moth (Attacus atlas) defies all preconceptions about moths’ small and dowdy nature.

 

Sometimes we have a tendency, as people who know about and spend time with insects, to find the level of disgust the British public feel towards invertebrates frustrating. That’s fair enough, but what scares people, scares them, and there’s nothing we can do except try to support those with true phobias and educate those who just don’t understand.

And whatever you do, don’t send mottephobes pictures of hawk moths!

 

 

Advertisements

Britain’s Next Top Pest

Moths montage2

Our Entomology MSc gang have just had two weeks hearing from some of the key players in the biological control industry. While there were many invasive insect pests mentioned that are currently giving UK growers cold sweats in the middle of the night, a few names kept cropping up.

Without further ado, here’s a run-down of just a few of the headline crop-hungry taxa posing new threats on these shores.

Spotted wing drosophila (Drosophila suzukii)

1024px-Drosophila_suzukii_combi1dd

Not the most appetizing plum, thanks to D. suzukii (photo: Martin Hauser/ Wikimedia Commons)

Despite its catchy name, nobody hopes to catch this fruit fly on their crop. Originally from South East Asia, it’s been rapidly expanding its range in Europe, and was first seen in the UK in August 2012. Unlike like other Drosophila, which tend to go in for decaying and rotten fruit, D. suzukii uses its serrated ovipositor to lay its eggs through the skins of otherwise undamaged fruit. A neat evolutionary advantage for it, really bad news for growers of soft fruit.

The pest control industry is very much all over trying to get the better of this species, though there is no perfect formula. Research has suggested that using biological methods, in this case entomopathic nematodes and fungi, can reduce population development, but can’t stop outbreaks.

South American tomato moth (Tuta absoluta)

Another great name, another insect to strike fear into growers. Unsurprisingly, it’s massively into tomatoes, and can do enormous damage to crops when left unchecked – to the point when they can finish off the lot. Although numbers of outbreaks in the UK are still relatively small, the potential to penetrate all parts of the tomato plant means that any arrivals, such as in imports of Spanish tomatoes, must be taken very seriously indeed.

pinworm larvae_3

The tomato isn’t looking great either (Photo: TNAU Agritech Portal)

Full development from egg to adult has been seen in a wide range of temperatures, and a 2013 study concluded that Tuta is “well able to develop under temperatures that would commonly be experienced in UK glasshouses”.

Other research has highlighted the potential of natural enemies to counter this tomato-loving moth, with Macrolophus and Nesidiocoris tenuis, two Hemipteran egg predators, now seen as having the best potential to make inroads into populations. The problem with this approach is that sometimes a beneficial insect can become a pest, and in this case, the biocontrols have been known to do plant damage themselves. Nothing is ever completely straightforward in the world of pest management, it seems.

Diamondback moth (Plutella xylostella)

There have been recent spikes in numbers of this lover of cabbage and cauliflowers, sparking natural concern among growers. Evidence is mounting that it’s surviving winter here, as well as resistant to pesticides.1280px-Plutella_xylostella1

The fight is by no means over, however. Intercropping – growing a different crop in proximity to the main one – looks like a promising tactic in taking on the pest. A 2010 study showed that planting onion, tomato or pepper with cabbage was as effective as spraying.

Melon thrips (Thrips palmi)

Thrips_palmi

Photo: Forestry Images/ Wikimedia Commons

Although this thrips species can’t survive the British winter, it can establish with protected crops, and is extremely unfussy in its choice of meal. As such, it’s as much a threat to growers of ornamental plants as it is to those in the fruit and veg business.

What’s more, it’s another insect known for being highly pesticide resistant, so effective biological controls are certainly what’s called for here. It seems likely that a mix of entomopathic nematodes and fungi may well be the dream team for tackling both the larval and adult stages.

 

Is that it?

Far, far from it. The insects featured here are certainly not the only ones that could potentially do significant harm in UK agriculture, should they both get the chance to arrive and find a way to consolidate their numbers here.

DEFRA’s top six of the very latest potentially damaging pests and diseases features a pair of longhorn beetles from the east, while the UK Plant Health Risk Register is a fascinating and somewhat frightening source of information about potential threats to the flora of this island. Currently listing 1,024 pests (not just insects, however), it serves to highlight that amidst the great advantages to global trade come some pretty serious pitfalls.

The prizes for pests that manage to establish themselves in the UK’s famously un-tropical climes are significant – and in an agricultural environment of reducing pesticide effectiveness and use, controlling their proliferation is a multi-faceted and often complex game.

Successful pest management has to take into account factors like the temperatures insects operate in, where they operate in the crop canopy, the need to tackle both adult and juvenile stages, and compatibility of biological control methods with insecticides and fungicides. It also needs to factor in a comprehensive clean-up after the pest has been beaten, to prevent an immediate repeat of the nightmare all over again.

While there are plenty of checks in place to try and prevent invasive pests getting the chance to test their resolve against the UK climate, it’s practically impossible to prevent every insect of potential harm making it past the border. The prerogative is that when they do show up, they are reported quickly, and expert advice sought when needed. If the last fortnight’s lecturers were anything to go by, there certainly is the expertise out there to nip most comers in the bud before scares become crises.

Behind the Moth Meme

Mothmeme1

Unless you’ve digitally cleansed your life recently, you’ll probably be aware that moth memes have taken over the internet – so much so that there is now, inevitably, a Reddit page dedicated to this unique sub-group of social media fodder.

The focus of this frenzy of meme-making has been moths’ famed love of artificial light. But here at Mastering Entomology, we’ve decided to delve a little deeper.

First and foremost, though, it’s worth pointing out that there are plenty of moths that fly during the day – so aren’t the types to be suckered into the seductive glow of a lamp. A study by Florida Museum of Natural History suggested that 15-25% of all Lepidoptera are day-flyers, while Butterfly Conservation has helpfully produced an overview of the UK’s non-nocturnal moths.

But of the nocturnal species, is there really a deep craving driving moth orientation towards our light sources? The fun-killing simple answer is probably no. The expert consensus seems to be that it’s all a misunderstanding; that they’re actually looking to orient themselves by the moon, and they’re simply drawn to alternatives because they’re brighter. As they move closer, their ability to triangulate is thrown off kilter, resulting in them returning to the light repeatedly.

Mothmeme3

But given the distraction, as opposed to attraction, our light sources bring, are all moths equally likely to zone in on the bright lights, and are all electric lighting types equally likely to bring lepidopterans into their glow? That’s another no and no.

The tendency to head for the light could be greater for moths from areas with little light pollution. Altermatt and Ebert (2016) found that in the case of the small ermine moth (Yponomeuta cagnagella), ‘city moths’ from populations that had experienced high amounts of artificial light were less likely to fly to light under lab conditions than those from ‘dark sky’ populations. It has been suggested by several studies that natural selection should favour those less drawn to artificial light – pretty logical stuff – and this research provides some evidence that such selection may indeed be happening.

Altermatt and Ebert have serious form when it comes to advancing knowledge on moths and light. In their 2009 study with Adrian Baumeyer, male Yponomeuta cagnagella and Ligdia adustata were seen to be 1.6 times more likely to make a beeline for an artificial light source than females. A good argument to settle the ‘smarter sex’ debate, perhaps.

A PhD study in Exeter has recently shed further light (pardon the pun) on the type of illumination most attractive to larger moths, finding that short wave lighting attracts both greater numbers of species and individuals than long wave.

Mothmeme2

The interplay of moths and light is, alas, not all online laughs and levity. There is growing evidence that artificial light may be having deeper effects on moth numbers than simply the deletion of those flying at speed towards the lamp. While the fact they are drawn to light is firmly established, there is evidence that it could be reducing moths’ attraction to each other.

A 2015 study in the Netherlands by van Geffen et al looked at the mating habits of Operophtera brumata, a member of the Geometridae family, when tree trunks were lit with different-coloured LED lighting. What the first phase of the research discovered was two-fold, and fascinating: a significant reduction in females on the illuminated trunks, again suggesting a sex bias in light attraction, and an inhibition of mating when they were under the lights. A side note, though: perhaps appropriately for this sexy moth discussion, more females caught on trunks lit with red light had mated than those with green or white light.

Mating is not the only matter that will pique concern amongst conservationists. Other research has found links between feeding and artificial light (they appeared to do less when subjected to it) and caterpillar development (they reached lower mass under white light and pupated earlier under green and white).

There is clearly multi-faceted interplay between moths and light, and a sense that we’re only beginning to understand the mechanics and effects of it. The ability of species to coexist with increasingly dense human habitation is a hot topic, so knowledge in this area is only set to grow in the coming years. Far from every aspect of this issue has been covered in this blog, but in the interests of brevity, it might be best to wrap up (although most of those readers who came for the memes have probably gone already).

Final note: this week and next we’re doing the taught elements of Biology and Taxonomy of Insects, the second module of the Entomology Masters here at Harper. Next Wednesday we’ll be looking at Lepidoptera, increasing our knowledge of these complex yet internet content-friendly insects.