Insect super powers: dodging death

Being near the bottom of the food chain isn’t ideal.  Insects have many different predators including lots from the insect world itself and that’s before you’ve even started to take account of all the birds, fish, reptiles, amphibians and mammals that consider insects an important part of their diet.  So how do insects dodge death and defend themselves against predators?  Read on to find out about some cunning techniques and surprising solutions!

Chemical Warfare

Did you know that some species of ladybird have clever, and some rather disgusting, ways of deterring predators?  Not only do many species display the bright warning colours of red or yellow combined with black, but some can exude a stinky yellow liquid through their knees when in danger.  This is called reflex bleeding because the liquid is made from their blood.  You may have noticed it if you have picked up a ladybird and seen yellow spots of liquid on your hand. 

Other insects can squirt noxious fluids into the air when they feel threatened.  Wood Ants, for example, spray formic acid.  The incredible Bombardier Beetle (seen here on the right) can combine two different liquids stored in separate chambers in its abdomen to produce a boiling hot chemical that literally explodes from the beetle’s rear. I wouldn’t like to be on the receiving end of that!

Cloaks of Invisibility

For many insects, protection from predators is all about not being seen.  There are some amazing masters of disguise whose camouflage is so good we have trouble spotting them.  For example, many moths are almost invisible when resting in their preferred habitat such as on the bark of trees.

How many insects can you spot?

Another form of camouflage is to disguise yourself as an object of no importance, such as a twig.  When threatened, this beetle (Platyrhinous resinosis) rolls over, draws in its legs, lies very still and looks just like a bird poo!

Platyrhinous resinosis

Masters of Disguise

If you can’t blend in with your background, you could always be a master of mimicry and pretend to be something really scary! This Hornet Clearwing is not actually a hornet with a powerful sting. It’s a moth, but by mimicking the colours and form of the hornet it will manage to put off many a hungry bird!

Serious Weaponry

Some insects have formidable weapons that may serve to fend off rivals, help catch prey and deter predators.  Look at the ferocious jaws of the Stag Beetle or the sharp pincers, or forceps, at the rear end of the earwig.  They might make you think twice before tackling these guys! In fact, the jaws of the Stag Beetle are all show!  They are actually quite weak and may even prevent Stag Beetles from feeding in their adult form. The fact that they exist at all just shows how effective they are at warding off predators.

Let us know if you have a favourite story about how insects dodge death and survive in a world full of predators.

The Dark Edged Bee-Fly

The Dark edged bee-fly, Bombylius major, is one of the most conspicuous insects to emerge in early spring because of it’s large size and ability to hover in mid air. It is the most common species of Bee-fly in the UK and can be seen in woodland, heathlands, grasslands and gardens from February to June. It has several other common names known as the ‘dark bordered beefly’ or ‘large beefly’. They get these names from their large size and from the dark wavy leading edge of their wings.

Dark edged bee-fly, Bobylius major. Image credit – Flickr / Jean-Marie Hamon, CC BY-SA 3.0

So, is it a bee or a fly? The single pair of wings tells us that this is a fly. A bee would have two pairs of wings. Why would a fly evolve to look like a bee? We think this is to trick predators into thinking it is more dangerous than it is. It certainly works with humans: many people think that the beefly has a large ‘sting’ at the front. In fact, this is just part the fly’s mouth and is quite harmless. The proboscis is adapted to drink the nectar from a wide variety of early-flowering plants. These include primrose, bugle, blackthorn, and cherry blossom. Because they transfer pollen from flower to flower, they are important pollinators in the spring.

Bee-fly feeding on nectar. You can see pollen grains on its legs and body. Image credit – Flickr / Robert Ault, CC BY-SA 2.0

Bee-flies may be harmless to humans but their life cycle is a bit grisly! Females lay their eggs in the underground nests of solitary mining bee nests such as Clarke’s Mining Bee (Andrena clarkella), the Early mining bee (Andrena haemarrohoa), and the Tawny mining bee (Andrena fulva). They collect sand or dust at the end of their abdomens. This sticks to their eggs, making them heavier. It may also help camouflage them. They then flick their eggs into the nest burrows of the bees. Once the eggs hatch, the bee-fly larvae crawl further down the burrows and wait for the bee larvae to grow until they are near full size. The bee-fly larvae then begin to feed on the mining bee larvae, drinking their body fluids and gradually eating them alive. When they have finished feeding, the bee-fly larvae then pupate and overwinter inside the burrow. The next generation of adult bee-flies then emerges from the burrows the following spring.

The Twany mining bee, Andrena fulva. Bee-fly larvae feed on its larvae. Image credit – Flickr / Line Sabroe, CC BY 2.0

You might think that means that bee-flies are bad for other bee species, but this is relationship evolved a long time ago and is part of the complex interaction between living things that exists in all ecosystems. Bee flies do feed on individual mining bees, but there is no evidence that they are harmful to bee populations.

If you spot a bee-fly this spring or summer, you can add your sighting to the national database by completing a simple online form on the Bee-fly Watch website. Why not let us know too? You could even take a picture or draw a picture. Who will spot the first bee-fly of 2021?

Insect super powers: surviving the winter

Insects have some really cool super powers and surviving extreme temperatures is one of them!  Have you ever wondered how insects manage to survive in the cold winter months? 

In the Summer, insects are all around us but in Winter they seem to disappear.  Where do they go and how do they survive the extremes of winter?  Unlike us, insects can’t put on a coat, hat and gloves or turn up the central heating!  With such a small body size, they could easily freeze as the temperature drops but they have some pretty cool ways of making sure their species continues to the next generation.

Take a look at these ideas. Who you think is right? Do you have a different idea?

Zane, Zeb, Zora and Zip are all right!

Strategy 1: Diapause

This is similar to mammalian hibernation where adults survive the winter in a state of torpor or dormancy.  Insects find suitable places to spend the winter such as holes in dead wood, under leaf litter or inside sheds and other buildings. They then become inactive, their heart rate slows right down and some insects even produce anti-freeze chemicals to stop them from freezing. 

Here are some insect species that undergo diapause:

During the Winter, only the queen bumblebee survives and amazingly all the other bumblebees die.  The queen spends the winter in an underground burrow already carrying the eggs that will be the next generation.

Butterflies such as Peacocks, Brimstones and Red Admirals shelter in garden sheds during diapause.  Sometimes you can find them inside houses – do not disturb!

Ladybirds huddle together in groups, for example, under bark of trees.

Strategy 2: Seasonal Lifecycles

The adult form of many insect species will not survive the winter but one of the other stages of their lifecycle (either the eggs, larvae or chrysalises) will survive by keeping warm in places such as leaf litter, under bark or in long grass waiting to be activated by the warmth of the sun in the spring.

The larval stage of the Stag Beetle and the Purple Emperor butterfly survive the winter, but the adults die.

Strategy 3: Migration

A few British insects such as the Painted Lady and Clouded Yellow butterflies migrate to Africa for the Winter.  Individual Painted Ladies have been recorded making journeys of nearly 2,500 miles. Unlike birds, the same individuals do not make the return journey the following year – that journey is made by a new generation.

Strategy 4:  Remain Active

Lots of insects do, in fact, remain active in the winter.  It is just harder to find them because they are keeping warm under leaf litter, amongst long grass or, in the case of aquatic insects, under water.  Most insects who do this are just feeding and waiting for the Spring when they can find a mate and reproduce but some species, such as Winter Moths and December Moths, reproduce during the winter months.

We would love to see your photos or hear about insects you have seen this Winter. What can you find in your garden or local outside spaces?  Be careful not to disturb them too much! You can tell us about it using the form on our Contact Us page, or email us at hopelearning@oum.ox.ac.uk.

The November Moth

The insect of the month has to be the November Moth, Epirrita dilutata. This moth is widespread in the UK and, although it gets its common name from its appearance in November, you can spot adults flying throughout the autumn in woods, hedgerows, parks and gardens.

The wingspan is 38-44mm with a dark wavy pattern against a lighter background. It’s easy to easy to mix this moth up with two similar species, the pale November moth E. christyi and the Autumnal Moth E. autumnata, both of which look similar. To make things even more confusing, all three species also have darker forms!

The caterpillar can be found in the spring and summer months feeding on a range of deciduous trees and shrubs. It is one of the ‘inch worms’ or ‘loopers’ that move by stretching out, then bringing their rear end forward to meet the front, forming a loop. They the stretch their front end out again and repeat the process. They are about an inch (2.5cm) long so it looks as if they are measuring as they move along.

Welcome to Crunchy on the Outside!

Crunchy on the outside is a new blog for and by young entomologists.

Interested in insects? Perhaps you saw something we posted online, came to the museum, or maybe we visited you at school for an Insect Discovery Day. However you heard of us, if you’re interested in insects this is the place for you!

We’ll be sharing news about insects and the natural world, people who work insects and help to protect them, what goes on at the museum, and new things for you to make and do. Look out for:

  • A peek behind the scenes at the museum
  • Insect related things to make and do
  • Info about people who work with insects, both past and present
  • Cool facts and stories about the amazing insects we can find in this country
  • A chance to have your say regarding what is in this blog and the museum
  • First dibs on related events

Crunchy on the outside is your opportunity to tell us what you would like from the museum, share your ideas and to get involved. We’d love to hear your ideas so please get in touch using the CONTACT US page if there is something you’d like to see.

Crunchy on the outside is part of the HOPE for the Future project at Oxford University Museum of Natural History. The project is funded by the National Lottery Heritage Fund.