Arthropedia - Marvellous March

The Entomologist’s Year: What To Look For In Spring (Part 1).

The classic Ladybird Book ‘What To Look For In Spring’ unfortunately only features a scant handful of insects. ‘Arthropedia: an illustrated alphabet of invertebrates’ on the other hand is stuffed to the brim with them, reflecting the author’s obsession!

Marvellous March

March is officially the start of spring (according to the Met Office) when we can look forward to a bonanza of butterflies, bees and other insects but in the first few days it doesn’t always feel that way. I have often had much balmier spring-like weather in mid February than I have in early March.

A Dandelion flower with a nectaring Peacock butterfly is a sight to gladden the heart, especially after a long cold winter.

Pond Life

A sure sign of spring: Frogs congregating in our garden pond and the first clumps of spawn.

Whatever the weather does, the natural world is telling us that it really is spring. You only need to see the blossom coming out in the hedgerows or watch frogs congregating in ponds to confirm it. And speaking of ponds, I like nothing more than whiling away some time watching the Frogs in my garden, checking to see when the first spawn is laid. Peering into the water between the weed, I will hopefully catch a glimpse of a Smooth Newt or two who also come to the pond to breed, and to feast on the tadpoles when they hatch!

A Smooth Newt waiting for the annual banquet of tadpoles to arrive.

The pond is home to some interesting invertebrates too. The last couple of years I’ve been fortunate to have the larvae of the soldier fly Stratiomys potamida in residence. These alien-looking beasts have an elongated ‘tail’ that they push up through the surface film to breath. They can sometimes be seen around the edge of the pond. The spectacular black and yellow fly emerges in July and is commonly called a Banded General.

The strange aquatic larvae of *Stratiomys potamida* (above) and the adult fly (below).

Another pond dweller, which is active throughout the year, is the so-called Water Hoglouse, Asellus aquaticus. This strange looking creature is a crustacean in the Order Isopoda and is related to the woodlice. Like a woodlouse, it has seven pairs of legs although they are of differing lengths, increasing in size from front to back. They feed on decaying organic matter and are often more active at night when they can be seen crawling over submerged plants.

Another aquatic invertebrate to look out for is the Water Cricket Velia caprai. It is a surface dweller much like the familiar Pond Skater but is generally found on faster flowing water like streams. They can sometimes be found in winter, unlike the Pond Skater which over-winters away from water. The Water Cricket has a neat little trick of spitting on the water to reduce the surface tension so that it can travel at a much faster pace.

Water Cricket. This one was photographed in June but adults can be found much earlier in the year.

The Early Flower Gets the Bees, and the Butterflies…

Flowering Currant is an important early source of nectar in our garden and is visited by various bumblebees and the solitary bee *Anthophora plumipes*, like this female.

Away from the pond, the first spring bees will be putting in an appearance. The Hairy-footed Flower Bee (Anthophora plumipes) will be patrolling patches of Red Dead-nettles and more bumblebees will be emerging, including the first ‘cuckoos’. These bees do not make their own nest but instead the female will seek out a new colony of another species of bumblebee, take it over by ousting or even killing the resident queen, then getting the workers to raise her own offspring. As the females don’t go to the bother of provisioning their own nest, they do not need any apparatus for collecting pollen so their hind leg lacks a scopa.

*Bombus hortorum* on Primrose (above) with a little pollen stuck to the scopa on her hind leg. Below a cuckoo bumblebee *Bombus vestalis* showing the unmodified hind leg.

One of the earliest mining bees, Andrena clarkella is out in March. Although they are solitary bees, they can form quite last nesting aggregations in suitable bare sandy soil. The females gather pollen almost exclusively from willows but will take nectar from other early flowers. If you are lucky enough to find a nest site then look out for the Early Nomad Bee (Nomada leucophthalma) which lays its eggs in the nest cells of the Andrena bee. When the Nomada larva hatches, it eats the pollen/nectar provisions in the cell, starving the Andrena larva. These bees are known as cleptoparasites as they steal the food of the host larva, thus killing them.

A female *Andrena clarkella* (above) and its cleptoparasite *Nomada leucophthalma*.

Overwintering butterflies will be on the wing on sunny days, stopping to nectar on the first Dandelions or early blossoms of Cherry Plum, Blackthorn and Sallow.

Comma on Sallow. The classic ‘Pussy Willow’ catkins are an important source of nectar and pollen for spring insects.

March also sees some nice hoverflies on the wing too, including early species that are often under-recorded due to the vagaries of spring weather. Like butterflies, they are often to be found on sallow catkins and Cherry Plum. Two of them are in the genus Cheilosia, namely C. albipila and C. grossa. They are very similar to each other, most easily told apart by the colour of their antennae (orange in albipila and black in grossa). They both have larvae that develop in the stems of thistles.

*Cheilosia albipila* (above) on Cherry Plum blossom and *Cheilosia grossa* (below) on Lesser Celandine, two early flying species of hoverfly.

The other early species of hoverfly to look out for is the spectacular Criorhina ranunculi. This species is a bumblebee mimic and it has two colour forms, one with a white ‘tail’ and the other with a red one. They fly with a distinct buzzing sound, further resembling a bee. This type of mimicry is presumed to prevent predation from birds that will have learnt not to try and eat bees because they are armed with a sting then apply the same assumption to the defenceless hoverfly.

*Criorhina ranunculi* can be hard to spot high up on blossom (above) but is pretty unmistakable when you get a good view.

Heavenly Heathland

Heathland is a treat to explore for wildlife at any time of year but spring is really special for me as this is when I am most likely to encounter an Adder. As well as these beautiful reptiles, there are all sorts of interesting invertebrates to look out for on a good patch of heathland, although many of them won’t be out until later in the year, so I will be revisiting heathland in future Blog posts.

One of the highlights of spring for me is watching basking Adders.

Gorse bushes provide ideal shelter over the winter for all sorts of creatures including ladybirds which will be on the move in the spring sunshine. Here you can also find Gorse Shieldbugs (Piezodorus lituratus) on mild sunny days and several species of bee take pollen and nectar from Common Gorse flowers.

Spiky gorse bushes provide a safe haven for a variety of insects. Here a Gorse Shieldbug and several 16 Spot Ladybirds have taken advantage of the same cover and are now warming up in the spring sunshine.

Two male *Andrena haemorrhoa* bees on Common Gorse. Males swarm around the flowers (known as lekking), waiting for newly emerged females who come to the flowers to collect pollen and nectar.

Look out for Minotaur Beetles (Typhaeus typhoeus) on heathland too, the large entrances to their burrows are often a give away to their presence in spring. The female beetle lays her eggs in a tunnel that she provisions with Rabbit droppings or other dung. The adult beetles emerge in spring.

Minotaur Beetles are a heathland favourite and can be encountered in spring when they emerge from their burrows.

Another heathland speciality is the Orange Underwing moth, a day-flying species that is on the wing in March and April. The caterpillars feed on Birch leaves and the adults can be seen flying high up around the trees on warm sunny days. Another early heathland moth, also associated with Birch, is the Yellow Horned. This species flies at night although you may be lucky enough to find one at rest during the day.

Orange Underwing from ‘U is for Underwings’ (below) in ‘Arthropedia: an illustrated alphabet of invertebrates’

Yellow Horned moth found resting on Gorse.

Mottled Grey, another early moth that can be found on heathland where it feeds on various bedstraws.

Garden Moths

March is when I generally first put my moth trap out in the garden after a break over winter. I have tried trapping in the last couple of months of the year but have never caught anything and January and February are always moth-less too so I have long since given up trying. But milder nights see me reviving my past passion and optimistically flicking the light on. Usually numbers are low and include the usual suspects of Hebrew Character, Chestnut, Common Quaker and Early Grey but we have also had the lovely Oak Beauty a couple of times. The spectacular hawk moths won’t be around until much later in the year, although the Lime Hawk is on the wing in May.

Hebrew Character, a common spring species.

Common Quaker nestled in an egg box in the trap.

Oak Beauty, one of the nicest moths from our trap in March. This rather robust moth is actually a Geometer. Other species in this Family are generally much more delicate looking.

And finally, if I’m lucky and it is a mild spring, the end of the month should see the first bee-fly on the wing in my garden. This is one of my all time favourite flies but you’ll have to wait until the next Blog post when I talk about the delights to find in April to find out about them.