The European hornet (Vespa crabo) is an eusocial insect.  That is to say, hornets live in colonies, with some 200 / 400 individuals in each colony.  A colony is founded by a fertilised queen, who emerges from hibernation in spring. Hornet queens are the sole survivors of an old colony after  a UK winter and they emerge as the weather finally starts to warm in early spring.  They then seek a warm, dry place to start nest construction. Once a nest location has been secured, they lay eggs that hatch into larvae.  The larvae are fed on protein-rich food (chewed up insects) and then they pupate; undergoing metamorphosis [a complete reorganisation of the body].  An adult hornet worker then emerges from the pupa some two weeks later.   These are ‘sterile’ female workers, who take over nest building and collecting food for the next set of developing larvae.   The developing colony lives within the papery nest its a (a bit like papier mâché), adding to the structure as the colony grows.  Twigs, bark and other plant material is broken up, chewed and shaped to form the nest. This material is glued together by their saliva.  Larvae that hatch in the summer are either fertile queens or males.  The males (drones) do not contribute to nest building, food foraging etc.  But in autumn, the males (drones) and the new queens leave the nest to mate.  The fertilised queens hibernate over winter, emerging in spring to start a new nest.  The ‘sterile workers’ and the male hornets die with the onset of winter. In other colonies of social insects, like honeybees, female workers don’t reproduce due to the pheromones that are released by the Queen. This was thought to be the case for European hornets but instead worker hornets enforce ‘sterility’ by physically destroying any worker-laid eggs or the workers laying them ! The food of a hornet is surprisingly varied. They can hunt and capture a wide variety of invertebrate prey (beetles, wasps, moths, dragonflies, robber flies - they may even prey on honey bees).  In many ways, hornets are useful in that they predate on a number of  garden and agricultural pests. Much of this prey is then chewed up to feed the growing larvae.  In return for this material, the larvae willingly ‘exude’ for the adults  a sugary liquid for them to feed on. Adults can also be found feeding on sugar-rich sources such as tree sap, nectar, and ripe fruit. They are more likely to ‘scavenge’ food at the end of summer into autumn rather than hunt.  The head of the insect has dark, prominent eyes, its wings are a reddish-orange, whilst the abdomen is striped with yellow and brown.  Hairs are present on both thorax and abdomen but they are not ‘hairy’ like bumblebees.  The colour of hornets can vary and a number of regional colour forms are known across Europe.  Worker hornets are about 25 mm in length, whilst queens may be up to 35 mm., so significantly bigger than wasps.  Partly because of its colour and size, a hornet can be mistaken for the Asian Giant Hornet (previously reported on in the woodlands blog).  However, a recent report indicates that the european hornet can attack and kill the Asian Hornet, by biting its head off.  Asian hornets are a considerable worry as they attack and kill  honey bees, plus their venom can induce life threatening anaphylactic shock. Breaking news : Asian hornets seen in Essex.   https://www.independent.co.uk/climate-change/news/asian-hornet-uk-bees-insects-b2177217.html In the past, the European hornet was rarely seen in the UK, being largely confined to areas of central southern England, but it has expanded in range in more recent times and is to be found across the South East and even in some more northerly locations.  Female hornets (but not males) have a stinger.  The venom within the stinger contains mixture of various neurotransmitters (serotonin, dopamine, histamine) as well as a concoction of enzymes.  Best avoided !  

In Norfolk, a ladybird is sometimes referred to as a bishy barnabee.; this rather curious name is explored in this article in The Spectator from last year.   Ladybirds are beetles and are easy to recognise. Most have dome-shaped bodies, with an oval outline and three pairs of jointed legs.  The most common ladybirds have bright red wing cases with black spots covering their bodies.  Others are yellow with black spots, some white and brown, or even striped.  It has been estimated that there are some five thousand species of ladybird across the world, with 40+ species in the British Isles. Their bright colour serves as a ‘do not eat me’ warning to would-be predators, apparently they have a bitter taste.  Birds such as swifts and swallows eat ladybirds, as do some spiders, frogs, wasps, and dragonflies.  When challenged, ladybirds can produce an ‘unpleasant’, yellow, oily fluid; or they may ‘play dead’.  The pine ladybird when under threat ‘clamps’ itself to the surface that it is resting on.  Bright colours are used as a defence mechanism in a number of insects. Read more...

The results of this year’s Big Butterfly Count are now available online and are discussed here : http://butterfly-conservation.org/48-13538/mystery-of-butterfly-disaster-summer.html. Sadly it is clear that a number of butterfly populations have fallen as compared to last year.   Indeed the numbers are the worst recorded since the start of the BBC (Big Butterfly Count). Numbers were lower than those recorded in 2012 when there was a cold and wet summer – which is never conducive to any aspect of the life cycle of butterflies (egg / caterpillar/ chrysalis / imago). Read more...

The British have always been inclined to talk about the weather “it's been too hot, too cold, been raining for days etc”.  However, there is now some justification for discussing the weather as recent years have seen the number of extreme weather events increasing and there have been significant changes in the ‘pattern of the weather”. Though not extreme, the weather this Spring and early Summer has been been disappointing.  Sleet and snow fell in late April, and there were a number of sharp frosts.  The April temperature was 6.5o C, 0.9o C below the 20 year long term average.  Most regions were colder and wetter.  This pattern continued into June.  This sort of weather, when coupled with last year’s rather cold , wet summer has significant effects on both insect and bird populations. Read more...

Different species of bumblebees make their nests in different places (using feathers, hair, dried moss or grass or materials for loft insulation). White tailed bumblebees.       May be found under the floor of garden sheds Buff tailed bumblebees.           May use air bricks and nest in the cavity walls of house Early bumblebees.                     Often use old birds’ nests in trees Carder bees                                 May use grass tussocks, dry leaves e.g. Under bramble thickets Tree bumblebees                        Make use of holes in tree trunk Wherever the nest is, the queen collects and forms a ball of the insulation material in a central space. https://www.youtube.com/watch?v=GCYUTRw-VZI Then, the queen constructs a ‘cup’ of wax.   This wax is produced by glands along the body, and molded by the legs and mouthparts (mandibles). Once formed, the wax ‘cup’ is filled with honey (essentially concentrated nectar). In addition to foraging for nectar, the queen will collect pollen which, with the addition of some nectar /honey, is fashioned into a small, pea-sized ‘ball’. The ‘ball’ is finally covered in a layer of wax. If the queen has fed well, then her ovaries will have developed and will be ready to lay eggs. The eggs are fertilised as they pass out of the body, using sperm stored from the mating that happened the previous year. A batch of eggs (usually 16) is placed inside the ‘pollen ball’, which is again sealed up with wax. The eggs are ‘sausage shape’ and cream in colour. Once inside the pollen ball, the bumblebee eggs are incubated - rather like the care extended to birds’ eggs.   They are kept warm by heat energy generated by the queen – who shivers and her muscles generate heat energy to warm the eggs. Shivering uses up energy at a prodigious rate, so the queen makes use of the nectar/honey store.   However, this does not last so the queen has to leave the nest (in search of nectar); but the eggs cannot be left for long or they will cool and development will slow (or cease). If kept at the right temperature, the eggs will produce grubs or larvae in about four days. The larval stage of all insects is a feeding stage – in which the animal builds up cells and tissues; and grows. In order to grow though, the larva / grub has to shed its skin / cuticle (this moulting is known as ecdysis) and the new one (formed beneath the old one) allows for expansion.  Moulting happens three times within 12 / 14 days and the grubs increase in size substantially. Next, the grub / larvae spins a cocoon from a protein thread. Within this, pupation and metamorphosis occurs. The tissues of the larva are completely remodeled – to form antennae, eyes, legs, distinct internal organs. This transformation takes about two weeks – at the end of which time, a recognizable (but white) bee emerges. To be continued .......

Phytomyza ilicis is a (dipteran) fly that lays its eggs in holly leaves.  It is one of the few insects that is able to make use of holly leaves as a food source and somewhere to live (when a larva).  The female fly lays eggs in the holly leaf (near the main veins or midrib – on the underside) using a thin tube or ovipositor.  The eggs are usually laid in early Spring when there are young and ‘soft’ leaves.  Older leaves have a thick and tough cuticle that is far more difficult to penetrate.  The larvae or maggots emerge from the eggs and tunnel their way along the midrib / veins emerging some time later into the lamina or blade of the leaf.  Here they feed on the photosynthetic tissues of the leaf – the palisade and mesophyll layers, creating a leaf mine (see featured image above).  The number of leaf mines per leaf is a maximum of three and often just 1 or two. Read more...