Hornet moth

Sesia apiformis is found across mainland Europe, Great Britain, and in parts of the Middle East. It has also recently been introduced to America and Canada. == Habitat ==

Adult hornet moths are often found in open habitat such as parks, golf courses, and marshy areas. Females prefer to lay eggs on old or isolated trees, especially trees surrounded by vegetation. == Food resources ==

Larvae feed on host trees of several poplar species including Populus tremula and Populus nigra as well as Salix caprea. == Life history ==

Egg Eggs of S. apiformis are brown and ovular in shape and have a major diameter of 0.43–0.85 mm. They are laid mostly around the base of an isolated tree or in surrounding vegetation. Larva S. apiformis larvae hatch from September to May and spend two or three years in the larval stage, overwintering as larvae. Adult hornet moths have clear wings that span 34–50 mm. Females and males both have yellow and black striped abdomens, but the number of stripes varies; females have two stripes whereas males have three. Females are on average larger than males. == Enemies ==

The primary predators of S. apiformis are bird species such as magpies and great tits, which is unexpected given the moths Batesian mimicry, as these birds are not among the species that eat hornets. A likely explanation for this phenomenon is an absence of the model hornet, which would lead to a decreased efficacy of the mimicry. This could lead to the conspicuous coloration having the opposite intended effect once birds realize that the hornet moth is harmless and begin to seek it out. == Protective coloration ==

The coloration of S. apiformis is an example of Batesian mimicry, as it resembles the coloration of hornets. The moth is as large as a hornet and even has the hornet's rather jerky flight when disturbed, but it has more yellow and lacks the waist between the abdomen and the thorax. This provides it protection from predators who want to avoid being stung and thus do not try to eat the moth. == Mating ==

Mate searching Female S. apiformis use specialized posterior glands to emit sex pheromones in order to attract potential mates. When the female is ready to mate, usually very soon after emerging from the pupae, she raises her abdomen and releases pheromones for several minutes at a time. The effectiveness of this calling is crucial for mating as the moths have only a short lifespan in which to mate and reproduce. Female-Male interaction The male S. apiformis does not appear to exhibit any courtship behavior; as soon as a male and female come into contact they are likely to begin mating. After the female has mated with one male, she will not wait to mate again. Each female usually mates several times before laying eggs. Males also do not appear to show a preference for virgin females as they will begin trying to mate with a female almost immediately after she has finished mating. Copulation is performed on the trunk of a tree with the female positioned above the male. == Interactions with humans ==

Pest Due to the large dieback of poplar trees across eastern United Kingdom and the association of boring larvae, S. apiformis has often been considered an agricultural pest. However, recent evidence suggests that the moth is not the primary driver of poplar tree dieback but rather increases the effects due to drought and human influence. Attempts to control the species have used the sex pheromones of S. apiformis females to create traps that attract individuals of the species. Conservation Populations of S. apiformis in the United Kingdom have shown evidence of decline over the past couple decades. While the adult forms are elusive and therefore have always been difficult to observe in the wild, the partially protruding pupae that are left after adult emergence provide a proxy for the number of moths in an ecosystem. In several sites around southern England where old exit holes were found, no new exit holes were found in trees, suggesting local population extinction. This coupled with the under-reporting of the species has led it to be classified as nationally scarce in the United Kingdom. ==Similar species==

• British Isles Sesia bembeciformis (lunar hornet moth) smaller with black head and shoulders. • Europe Eusphecia melanocephala Dalman 1816 • Europe Eusphecia pimplaeformis Oberthür 1872 ==Gallery==

File:Sesia apiformis damage.jpg|Damage File:Sesia apiformis larva.jpg|Larva File:Sesia apiformis pupa.jpg|Pupa File:Sesia apiformis on leaf.jpg|Adult Female File:Sesia_apiformis_mounted.jpg|Adult Male File:Sesia apiformis 02.jpg|Mating File:Sesia apiformis and bembeciformis side by side.jpg |Sesia apiformis and S. bembeciformis side by side ==References==