Sperm competition is the competitive process between spermatozoa of two or more different males to fertilize the same egg during sexual reproduction. Competition can occur when females have multiple potential mating partners. Greater choice and variety of mates increases a female's chance to produce more viable offspring. However, multiple mates for a female means each individual male has decreased chances of producing offspring. Sperm competition is an evolutionary pressure on males, and has led to the development of adaptations to increase males' chance of reproductive success. Sperm competition results in a sexual conflict of interest between males and females. Males have evolved several defensive tactics including: mate-guarding, mating plugs, and releasing toxic seminal substances to reduce female re-mating tendencies to cope with sperm competition. Offensive tactics of sperm competition involve direct interference by one male on the reproductive success of another male, for instance by physically removing another male's sperm prior to mating with a female. For an example, see Gryllus bimaculatus.
The deathwatch beetle is a species of woodboring beetle that sometimes infests the structural timbers of old buildings. The adult beetle is brown and measures on average 7 mm (0.3 in) long. Eggs are laid in dark crevices in old wood inside buildings, trees, and inside tunnels left behind by previous larvae. The larvae bore into the timber, feeding for up to ten years before pupating, and later emerging from the wood as adult beetles. Timber that has been damp and is affected by fungal decay is soft enough for the larvae to chew through. They obtain sufficient nourishment by using a number of enzymes present in their gut to digest the cellulose and hemicellulose in the wood.
The marginal value theorem (MVT) is an optimality model that usually describes the behavior of an optimally foraging individual in a system where resources are located in discrete patches separated by areas with no resources. Due to the resource-free space, animals must spend time traveling between patches. The MVT can also be applied to other situations in which organisms face diminishing returns.
Animal sexual behaviour takes many different forms, including within the same species. Common mating or reproductively motivated systems include monogamy, polygyny, polyandry, polygamy and promiscuity. Other sexual behaviour may be reproductively motivated or non-reproductively motivated.
The greater vasa parrot is one of two species of vasa parrot, the other being the lesser vasa parrot C. nigra. The greater vasa parrot can be found throughout Madagascar and the Comoros.
Sexual cannibalism is when a female cannibalizes her mate prior to, or after copulation. It has evolved by natural selection in many arachnid orders and several insect orders. Several hypotheses to explain the evolution of this seemingly paradoxical behaviour have been proposed. The adaptive foraging hypothesis, aggressive spillover hypothesis and mistaken identity hypothesis are among the proposed hypotheses to explain how sexual cannibalism evolved. This behavior is believed to have evolved as a manifestation of sexual conflict, occurring when the reproductive interests of males and females differ. In many species that exhibit sexual cannibalism, the female consumes the male upon detection. Females of cannibalistic species are generally hostile and unwilling to mate; thus many males of these species have developed adaptive behaviors to counteract female aggression.
The red flour beetle is a species of beetle in the family Tenebrionidae, the darkling beetles. It is a worldwide pest of stored products, particularly food grains, and a model organism for ethological and food safety research.
Oiceoptoma noveboracense is a member of the family Silphidae, or carrion beetles, which feed on decaying organic matter such as dead animals. Its common name is the margined carrion beetle, from the orange-red margins on the pronotum, which are helpful when identifying this species. The larva is typically light brown to red and also has vertical ridges on its thorax like the adult. This diurnal beetle can be found mainly in the spring into the fall, and it has a strong preference towards a deciduous forest habitat. The primary forensic importance of this beetle is its ability to use the succession of insect fauna to provide confirmation of postmortem intervals.
Lestes sponsa, is a damselfly, with a wide Palaearctic distribution. It is known commonly as the emerald damselfly or common spreadwing. Both males and females have a metallic green colour and when resting its wings are usually half opened.
Callipogon relictus is a species of longhorn beetle which is mostly found in Korea, but also in China and southern part of Russian Far East. It inhabits mixed and deciduous forests. The population of Callipogon relictus is decreasing due to deforestation and uncontrolled collection, and therefore the species are listed in the Russian Red Book.
Stenurella melanura is a flower longhorn beetle species of the family Cerambycidae, subfamily Lepturinae.
The rufous grasshopper or Gomphocerippus rufus, is a medium-sized, broad, brown, 'short-horned' grasshopper with clubbed antennae that are tipped with a conspicuous white or pale colour. It is fairly large, averaging 14 to 22 mm in length. It is of the subfamily Gomphocerinae in the family Acrididae, the predominant family of grasshoppers. This species is present in most of Europe, in the eastern Palearctic ecozone and in the Near East. It can be encountered from late July through mid-December, usually in dry or slightly moist habitats. The environments in which it typically resides include dry grassland on calcareous soils, sheltered valleys with scrub, and the open borders of forests. It feeds on grasses and various herbaceous plants. It is known for its distinctive courtship song and accompanying display.
Bolitotherus cornutus is a North American species of darkling beetle known as the horned fungus beetle or forked fungus beetle. As a holometabolic insect, its life cycle includes four life stages: egg, larva, pupa, and adult. All life stages are associated with the fruiting bodies of a wood-decaying shelf fungus, commonly Ganoderma applanatum, Ganoderma tsugae, and Ganoderma lucidum.
Hylobittacus apicalis is a species of hangingfly in the order Mecoptera, and the only species within the genus Hylobittacus.
Sexual selection in scaled reptiles studies how sexual selection manifests in snakes and lizards, which constitute the order Squamata of reptiles. Each of the over three thousand snakes use different tactics in acquiring mates. Ritual combat between males for the females they want to mate with includes topping, a behavior exh wrongibited by most viperids in which one male will twist around the vertically elevated fore body of its opponent and forcing it downward. It is common for neck biting to occur while the snakes are entwined.
Sexual coercion in animals is the use of violence, threats, harassment, and other tactics to help them forcefully copulate. Such behavior has been compared to sexual assault, including rape, among humans.
Cryptic female choice is a form of mate choice which occurs both in pre and post copulatory circumstances when females in certain species use physical or chemical mechanisms to control a male's success of fertilizing their ova or ovum; i.e. by selecting whether sperm are successful in fertilizing their eggs or not. It occurs in internally-fertilizing species and involves differential use of sperm by females when sperm are available in the reproductive tract.
In behavioral ecology, polyandry is a class of mating system where one female mates with several males in a breeding season. Polyandry is often compared to the polygyny system based on the cost and benefits incurred by members of each sex. Polygyny is where one male mates with several females in a breeding season . A common example of polyandrous mating can be found in the field cricket of the invertebrate order Orthoptera. Polyandrous behavior is also prominent in many other insect species, including the red flour beetle and the species of spider Stegodyphus lineatus. Polyandry also occurs in some primates such as marmosets, mammal groups, the marsupial genus' Antechinus and bandicoots, around 1% of all bird species, such as jacanas and dunnocks, insects such as honeybees, and fish such as pipefish.
Augochlora pura is a solitary sweat bee found primarily in the Eastern United States. It is known for its bright green color and its tendency to forage on a variety of plants. Inhabiting rotting logs, this bee can produce up to three generations per year. Both males and females have been observed licking sweat from human skin, most likely seeking salt
The lemon tree borer, also known as the whistling beetle or the singing beetle, is a longhorn beetle endemic to New Zealand. Its larvae are generalist feeders, boring into the wood of a wide variety of trees, native and introduced. When citrus orchards were first established in New Zealand, this beetle started inflicting serious damage, and so gained the name "lemon tree borer". Four species within the genus Oemona have been identified, suggesting that more species could be found. When disturbed by predators or humans, the adult beetle stridulates creating a "rasp" or "squeak" sound by rubbing its thorax and head together against an area of thin ridges. Māori would eat a liquid called "pia manuka", which was produced by manuka trees when its wood was damaged by the larva. When Captain Cook first arrived in NZ, his naturalists, Banks and Solander, collected a lemon tree borer in their first collection between 1769-1771. This oldest collected specimen can be found in the British Museum. A few years after the first collection, the species would be first described by the Danish naturalist Fabricius in 1775.
