Fabulous Fig Wasps

Many insects are important pollinators helping plants to make seeds from which new plants can grow. One of these is the fabulous fig wasp. In this video fig wasp researcher Sotiria Boutsi explains the amazing life cycle of the fig wasp, and why without it we wouldn’t have any figs!

Sotiria Boutsi shares her fascination with fig wasps

Sotiria shared her interest in fig wasps with Crunchy on the outside while she was a Professional Intern in Public Engagement at the Museum of Natural History. She has a Master’s degree in Conservation Biology and is currently researching for a PHD at Harper Adams University on using genetic information to study how different species of fig wasp are related to each other.

You can find out about other amazing insects in the Insects section of the blog.

Update: So, are there wasps in figs we eat?

Sotiria’s video sparked some debate on social media about whether there are wasps in the figs we eat. This is a complicated subject, but the short answer is ‘no’. Many figs that are produced for sale in supermarkets and greengrocer’s shops are ripened without the need for them to be pollinated by insects. Some figs produced for sale are pollinated by fig wasps, but the fig produces a chemical that dissolves the wasps.

So, any crunchy bits inside a fig are seeds, not wasps!

Header image: Fig wasps, Philocaenus rotundus, on a fig. Alan Manson CC BY 4.0

The Marvellous Maybug

As the month of April fades into May a certain beetle can be found flying noisily about its business. Cockchafers, often called Maybugs, are relatively large members of the Scarab beetle family. There are three different species of Cockchafer found in Europe;

  • The common cockchafer, Melolontha melolontha
  • The forest cockchafer, Melolontha hippocastani
  • The large cockchafer, Melolontha pectoralis

Cockchafers spend most of their lives, 3 to 4 years, as larva, living underground, munching away at the roots of plants. In large numbers they can become pests, doing significant damage to crops.

It is as adults that they emerge above ground, flying around for roughly 5 to 6 week looking for a mate and feeding on the leaves of trees. They can usually be spotted making their noisy flight at dusk on warm evenings. You may even find them flying into and around your outside lights.

Common Cockchafer (Melolontha melolontha) © OUMNH

They are around 3cm long, with reddish brown wing cases and distinctive fan shaped antennae. Despite their intimidating size and noisy flight, they are actually harmless to humans. I once had one fly in the house and land on my big toe, waking me up from a nap!

Pesticides used farming in the mid-1900s brought them to the brink of extinction in the UK. However, changes in farming practises and pesticide use has allowed them to make a comeback. They can now be found across England, are particularly common in the south of England and the Midlands. They are much rarer in Scotland.

Do you know of any other insects that are considered pests by farmers? Let us know in the comments below or via the contact us section of the blog.

Your questions answered: ‘Which is the most successful species of ant?’

Noah contacted us recently with an intriguing question: ‘What is the most successful species of ant?’. It really got us thinking! Insects are a very successful group of animals, and ants are very successful insects, but how could we decide which is the most successful?

There might be different ways we might measure success. It is the most numerous ant? Or the group with the most species? It might be the species that’s most widely spread across the globe? Perhaps it’s the longest-lived, or the largest?

Successful ants

Ants are a very successful group of insects. The biologist E.O. Wilson (who died recently) estimated that there may be a million ants for every human being, but the truth is that we don’t really know. Although they are small, there are so many of them that they may make up a quarter of the mass of all land animals!

Scientists think that ants probably evolved from a type of wasp 168 million years ago. They became really successful after flowering plants evolved about 100 million years ago. We know this because ants appear much more often in the fossil record, and we start to find many more species . One of the oldest fossil ants is Sphecomyrma, found trapped in 99 million year old amber from Myanmar.

Micrograph of a fossil ant trapped in amber. Species undetermined. 50 million years old.
Fossil Ant trapped in Amber. Image Credit: OUMNH

Features that have helped ants to become so successful include:

  • Their social nature – ants in a nest are good at cooperating.
  • They modify habitats – most animals can only survive in certain conditions but ant colonies can change their surroundings to suit them.
  • Ants can use a wide range of food sources. Some species even farm – growing fungi or ‘milking’ aphids for food.
  • Defence – ants are really good at defending themselves and each other. They are strong, have biting mouthparts and produce acid. The origin of the word ‘ant’ means ‘biter’.
  • Some species form supercolonies – huge nests containing several queen ants. This level of cooperation and organisation help some ant species to be mega-successful.
The ability of ants to cooperate helps make them successful.

Which ants are most successful?

So, ants are very successful as a group of insects. Here are some examples of ant species that might be the most successful:

Most numerous: Difficult to say, but perhaps the Argentine ant Linepithema humile.

Widest distribution: Several contenders for this, but perhaps the fire ant Solenopsis invicta.

Most different species: The genus Pheidole with over 1,000 described species.

Largest: The fossil giant ant Titanomyrma gigantuem was the largest ant to have lived. The queens were 6cm long with a wingspan of 15cm.That’s about the same size as a hummingbird!

Longest lived: We think oldest individual ant on record in a laboratory was a queen of the species Pogonomyrmex owyheei which lived to be 30 years old. Colonies of ants can survive for centuries in nature, continuing through many generations of ants.

The fossil giant ant Titanomyrma lubei, with a hummingbird for comparison.
Image Credit: Simon Fraser University CC BY 2.0

The fact is, however, that every species has most of the characteristics that make all ants successful, so perhaps the most common British ant, the Common Black Ant, Lasius niger, is as good a candidate for most successful as any? It’s also worth remembering that entomologists think we have only described about two thirds of all ant species – so there are many more left to discover!

We hope that answers Noah’s question. If you have a question about insects or the museum you’d like to ask us, just write it in the comments or send us a message using the Contact Us page.

The Red Tailed Mason Bee

You may well have noticed some bees recently. One of the earliest solitary bees to emerge in spring is the Red Tailed Mason Bee, Osmia bicolour. They are very distinctive and make their nests in a very particular place.

The males emerge first, sometimes as early as March. They have yellowish bands. They are the followed in a couple of weeks by females which have distinctive red-banded abdomens, giving this bee its common name. The adults may continue flying well into July, so you have plenty of time to spot them. This species of bee is mainly found across southern England and the Midlands and South Wales. This is because it prefers chalk and limestone grassland and so is mainly in areas with this type of habitat.

Female Red Tailed Mason Bee making a snail shell nest. Copyright © John Walters, used with kind permission.

The Red Tailed Mason Bee is unusual in that the females make their nests in empty snail shells. A female bee works diligently to select a suitable shell then prepare the nest. She will then defend this vigorously. She will make several cells within the spiral of one shell, laying an egg in each cell. She will provide each egg with pollen as food for the larvae when they hatch. She will separate each cell with a glue-like substance called mastic. She makes this by chewing up pieces of leaf. When the nest is completed, she will plug the shell with more mastic and will then search for debris such as grass stems, fallen leaves and pine needles to carefully cover and camouflage it. She may also spread more mastic over the outside of the shell.

Entomologists think it is likely that this behaviour protects the shell and its contents from parasites and predators. Safe inside, the eggs will hatch and the larvae will develop inside the shell, feeding on their supply of pollen. They will then survive the winter as pupae, emerging as the next generation of adults the following spring.

So, if you spot an old snail shell, it’s worth keeping an eye on it; it may just become a nest for a Red Tailed Mason Bee. We’d love to hear about your bee sightings and to see your pictures. Get in touch with us using the comments below or by the Contact Us page.

Header image: Red-tailed mason bee, Osmia bicolor female. Image: František ŠARŽÍK CC BY 3.0

BREAKING NEWS: Once in a lifetime insect emergence

There is a secretive and enigmatic species of moth that will only emerge from their pupa in very specific conditions, on the first day of April. These once in a lifetime conditions are due to be met in the Oxford area today.

The caterpillar of this insect sub species, known as the Lesser April Jester moth (Stulte aprilis dies), will find a sheltered, confined space in which to pupate. In nature, cracks in rocks are an ideal location, but it has adapted to built environments by using the gaps between paving stones. Here it will stay, for years or even decades, until the required environmental conditions are met. When a cold snap follows an unseasonably warm spell, the adult will emerge from the pupa. Entomologists from Oxford University Museum of Natural History believe that the weather we have experienced recently meets these conditions, and is the best chance to see emerging adults for several decades.

Specimen of Lesser April Jester moth (Stulte aprilis dies), collected in Oxford in 1951

The moth will exit the pupal case and, if necessary, will tunnel to the surface, squeezing out through the cracks in the pavement. It will unfurl its glorious, clear wings, displaying the red, blue, green and yellow stripes, on its back, for all to see. It will then fly off to find a mate, to ensure the next generation of this rarely seen insect.

Burrow of Lesser April Jester moth (Stulte aprilis dies) in pavement of Parks road, 1 April 1951

Unfortunately so many jester moths never make it out of their pupa, whether due to the required conditions never being met, or to not having enough energy to dig their way to the surface. If you wish to help, gently inserting and then removing small twigs between paving stones to loosen the soil can help to ease their paths.

The last know sightings in Oxfordshire occurred on Parks Road in Oxford on 1st April 1951. Please let us know if you catch sight of this moth, and even better please share any photos you may take either in the comments below, or via the Contact us page.

Bee-flies: A sign of Spring

At this time of year, after the long winter months, we are all looking for signs of Spring.   One thing that entomologists look forward to is the first sightings of bee-flies.   These very cute, furry flies start to emerge in late February and early March.

Bombylius major, the dark-edged bee-fly, is one of Erica McAlister’s favourite British insects and she tells us why in this video.

Find out more about Bee-flies

To find out more about bee-flies, check out this page on the Dipterists Forum. There is also an excellent guide to bee-fly identification which you can find here.

In addition, the Dipterists Forum run an annual Bee-fly Watch which gathers together records of sightings.  This is really important for monitoring changes in distribution and flight period.  You can contribute to this important science project by adding your sightings here:

Bee-fly Watch | Soldierflies and Allies Recording Scheme (brc.ac.uk)

Have you seen any bee-flies yet this Spring? Let us know, too, by telling us below or by using the Contact Us page.