Yellow-necked mouse

( Latin: Apodemus flavicollis)

Most yellow-necked mice spend the whole of the year out in the open, but some enter houses, usually later on than the house mice, about the end of October. They will eat stores of fruit in cellars or other places.

In the wild, yellow-necked mice feed on all kinds of seeds and they are very fond of hazelnuts and almonds. They are primarily woodland animals, which have spread to gardens and parks with scattered trees and bushes. They are common in many parts of Europe and also occur in southern England. The closely related wood mouse, Apodemus sylvaticus, is found throughout the British Isles and it also enters buildings in autumn.

House mouse

( Latin: Mus musculus)

Many house mice spend the summer out in the fields, but usually not far from houses. Then from the middle of August onwards they start to move indoors again, and the peak of such an invasion will usually be in the middle of September. See also p. 84 for more details on house mice.

Mice

When mice start to come into a house in autumn they will usually be house mice, wood mice or yellow-necked mice. Other species sometimes come indoors but they usually do not survive very long.
For precautions to be taken to prevent such invasions

Wasps

Often when the loft is being cleared in winter one comes across a very drowsy wasp hidden away in a well-sheltered spot. This will be a hibernating young queen

Seven-spotted ladybird

( Latin: Coccinella septempunctata)

In late summer ladybirds are often seen flying around in large numbers. They emerge from fields where the larvae have been feeding on aphids, and they gather in hedges and along the edges of woodland where they will spend the winter under bark or stones. They may also enter houses, where they are very commonly seen even in the middle of winter.

Butterflies1

( Latin: Lepidoptera)

Butterflies sometimes spend the winter in houses, usually in lofts. The species that commonly do this are the small tortoise- shell (Aglais urticae) and the peacock (Inachis io), which are seen in the typical resting position with the wings folded together over the back. They should not be disturbed, for if they come into the warmth they will soon die. In spring many of the butterflies that have overwintered in the house will die because, being attracted by the light, they fly against the windows until they have used up their last reserves, so it is a good idea to open the windows and let them fly out.

Cabbage white butterflies, such as the large white (Pieris brassicae), may overwinter, but in the pupal stage. These butterflies have more than one brood during the summer. The larvae of the last brood leave the plants they have been feeding on when they are ready to pupate. Sometimes roads and paths in the vicinity of a field of cabbages or swedes are alive with cabbage white caterpillars, searching for a sheltered place in which to pupate. They can be seen in their hundreds crawl up tree trunks, wooden fences or the walls of houses. When a suitable place has been found each caterpillar makes a base of fine silken threads, and attaches itself firmly to the substrate with a loop around its body. The larvae then moults again to produce a hard, angular, immobile pupa (Page 24). These pupae can be found in houses and other sheltered places throughout the winter. The adult butterflies emerge from them in the spring and fly out into the open.

Sometimes, instead of pupating in the normal way, a cabbage white caterpillar will stop feeding and a mass of tiny larvae will crawl out of it; sometimes they come out of the butterfly pupa. These larvae will then pupate immediately, each in a tiny yellow cocoon (see photograph p. 193), alongside the now empty caterpillar skin or pupal case. They are parasitic hymenopterans known as braconids and they have developed from eggs laid in the living caterpillar by a female braconid. The larval braconids have simply eaten the whole contents of the caterpillar.

Common gnat

( Latin: Culex pipiens)

This is a small, brownish mosquito or gnat, often found spending the winter in large numbers in, for instance, damp cellars. Sometimes it will take to the • wing during the winter if disturbed, but fortunately it seldom bites humans, evidently preferring the blood of birds.

Theobaldia annulata1

This is a large grey mosquito with white rings on the legs. The fertilized females spend the winter in suitable cool places, but if disturbed they may wake up and even start to suck blood. In fact this is the species that is nearly always responsible for mosquito bites in the middle of winter.

Gnats and mosquitoes

These are normally summer insects (see p. 47), but there are two species which are seen in winter, as they sometimes enter houses to spend the cold part of the year

Musca autumnalis

This is a relative of the common housefly, which it closely resembles, and indeed the two are difficult to distinguish. The eggs are laid in fresh cow pats in the fields and the larvae feed on the dung. The adult flies live around the cattle and are not seen indoors during the summer. In the autumn they sometimes enter outhouses and cool lofts where, like cluster flies, they hide away in cracks and crevices and re- main inactive throughout the winter. In spring they become active again and move out into the open, but they may wake up in winter if there is a warm spell.

Indeed, it is not uncommon to see flies indoors during the winter. Sometimes these may belong to the two species just described, but in many cases they will just be common houseflies (p. 77). In northern Europe these do not overwinter in any particular stage. Many spend the winter in warm farm buildings, where they may breed throughout the year, and may therefore appear in the house even in the middle of winter.