Hill-topping is a mate-location behaviour seen in many insect

Insect

Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s including butterflies

Butterfly

A butterfly is a mainly day-flying insect of the order Lepidoptera, which includes the butterflies and moths. Like other holometabolous insects, the butterfly's life cycle consists of four parts: egg, larva, pupa and adult. Most species are diurnal. Butterflies have large, often brightly coloured...

, dragonflies

Dragonfly

A dragonfly is a winged insect belonging to the order Odonata, the suborder Epiprocta or, in the strict sense, the infraorder Anisoptera . It is characterized by large multifaceted eyes, two pairs of strong transparent wings, and an elongated body...

, wasp

Wasp

The term wasp is typically defined as any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. Almost every pest insect species has at least one wasp species that preys upon it or parasitizes it, making wasps critically important in natural control of their...

s, beetle

Beetle

Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...

s and flies

Fly

True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...

.

Males of many butterfly species may be found flying up to and staying on a hilltop - for days on end if necessary. Females, desirous of mating, fly up the hill. Males dash around the top, competing for the best part of the area - usually the very top; as the male with the best territory at the top of the hill would have the best chance of mating with the occasional female, who knows the "top male" must be strong and thus genetically fit. Many authors consider this as a form of lekking behaviour. Many butterfly species including swallowtails, nymphalids

Nymphalidae

The Nymphalidae is a family of about 5,000 species of butterflies which are distributed throughout most of the world. These are usually medium sized to large butterflies. Most species have a reduced pair of forelegs and many hold their colourful wings flat when resting. They are also called...

, metal-marks

Riodinidae

The Riodinidae are a family of butterflies. The common name "metalmarks" refers to the small metallic-looking spots commonly found on their wings. There are approximately 1,000 species of metalmark butterflies in the world...

 and lycaenids

Lycaenidae

The Lycaenidae are the second-largest family of butterflies, with about 6000 species worldwide, whose members are also called gossamer-winged butterflies...

 are known to hill-top.

In some Acraea butterflies, widespread infection by Wolbachia

Wolbachia

Wolbachia is a genus of bacteria which infects arthropod species, including a high proportion of insects , as well as some nematodes. It is one of the world's most common parasitic microbes and is possibly the most common reproductive parasite in the biosphere...

results in a rarity of males and in these species the females widely engage in hill-topping behaviour. Female butterflies at hill-topping sites are predominantly of unmated individuals.

Studies have shown that even slight elevation differences on flat terrain can trigger hill-topping behaviour.

The concentrating effect of hill-topping on butterfly populations makes such locations of special conservation significance.

Recent studies in Stirling, Scotland, have provided some evidence of hilltopping in bees of the genus Bombus.