The Coolidge effect is a biological phenomenon seen in animals, whereby males exhibit renewed sexual interest whenever a new female is introduced to have sex with, even after cessation of sex with prior but still available sexual partners. To a lesser extent, the effect is also seen among females with regard to their mates.
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.
A spermatophore or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especially salamanders and arthropods, and transferred in entirety to the female's ovipore during reproduction. Spermatophores may additionally contain nourishment for the female, in which case it is called a nuptial gift, as in the instance of bush crickets. In the case of the toxic moth Utetheisa ornatrix, the spermatophore includes sperm, nutrients, and pyrrolizidine alkaloids which prevent predation because it is poisonous to most organisms. However, in some species such as the Edith's checkerspot butterfly, the "gift" provides little nutrient value. The weight of the spermatophore transferred at mating has little effect on female reproductive output.
Urosaurus ornatus, commonly known as the ornate tree lizard, is a species of lizard in the family Phrynosomatidae. The species is native to the southwestern United States and northwestern Mexico. The species, which formerly was commonly called simply the "tree lizard", has been used to study physiological changes during the fight-or-flight response as related to stress and aggressive competition. Its life history and costs of reproduction have been documented in field populations in New Mexico and Arizona. It has been fairly well studied because it has interesting variation in throat color in males that can correlate with different reproductive strategies,
Monogamous pairing in animals refers to the natural history of mating systems in which species pair bond to raise offspring. This is associated, usually implicitly, with sexual monogamy.
Gryllus bimaculatus is a species of cricket in the subfamily Gryllinae. Most commonly known as the two-spotted cricket, it has also been called the "African" or "Mediterranean field cricket", although its recorded distribution also includes much of Asia, including Korea, China and Indochina through to Borneo. It can be discriminated from other Gryllus species by the two dot-like marks on the base of its wings.
Sexual conflict or sexual antagonism occurs when the two sexes have conflicting optimal fitness strategies concerning reproduction, particularly over the mode and frequency of mating, potentially leading to an evolutionary arms race between males and females. In one example, males may benefit from multiple matings, while multiple matings may harm or endanger females, due to the anatomical differences of that species.
Teleogryllus oceanicus, commonly known as the Australian, Pacific or oceanic field cricket, is a cricket found across Oceania and in coastal Australia from Carnarvon in Western Australia and Rockhampton in north-east Queensland
Sexual cannibalism is when an animal cannibalizes its mate prior to, or after copulation. It is a trait observed in many arachnid orders and several insect orders. Several hypotheses to explain this seemingly paradoxical behavior 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.
Paracerceis sculpta is a species of marine isopod between 1.3 millimetres (0.05 in) and 10.3 mm (0.41 in) in length. The species lives mainly in the intertidal zone, and is native to the Northeast Pacific from Southern California to Mexico, but has since been introduced to many other countries. Adults are herbivorous and consume algae but juveniles are carnivorous and consume moulting females. They reproduce in sponges but do not feed near them.
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 realm, 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.
Metaplastes is a genus of bush crickets in the subfamily Phaneropterinae and tribe Barbitistini.
A nuptial gift is a nutritional gift given by one partner in some animals' sexual reproduction practices.
Dryomyza anilis is a common fly from the family Dryomyzidae. The fly is found through various areas in the Northern hemisphere and has brown and orange coloration with distinctive large red eyes. The life span of the fly is not known, but laboratory-reared males can live 28–178 days. D. anilis has recently been placed back in the genus Dryomyza, of which it is the type species. Dryomyzidae were previously part of Sciomyzidae but are now considered a separate family with two subfamilies.
Sexual selection in birds concerns how birds have evolved a variety of mating behaviors, with the peacock tail being perhaps the most famous example of sexual selection and the Fisherian runaway. Commonly occurring sexual dimorphisms such as size and color differences are energetically costly attributes that signal competitive breeding situations. Many types of avian sexual selection have been identified; intersexual selection, also known as female choice; and intrasexual competition, where individuals of the more abundant sex compete with each other for the privilege to mate. Sexually selected traits often evolve to become more pronounced in competitive breeding situations until the trait begins to limit the individual's fitness. Conflicts between an individual fitness and signaling adaptations ensure that sexually selected ornaments such as plumage coloration and courtship behavior are “honest” traits. Signals must be costly to ensure that only good-quality individuals can present these exaggerated sexual ornaments and behaviors.
Gryllus integer, commonly known as the western trilling cricket, is one of many species of field cricket in the genus Gryllus. It is called the "triller" field cricket because its song is nearly continuous rather than broken into discrete chirps. G. integer can be found in parts of the Western United States, having been recorded from Oregon, California, Arizona and New Mexico.
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.
Grylloidea is the superfamily of insects, in the order Orthoptera, known as crickets. It includes the "true crickets", scaly crickets, wood crickets and other families, some only known from fossils.
Hemiandrus maculifrons is a species of ground wētā endemic to New Zealand. They are nocturnal, carnivorous, and flightless orthopterans belonging to the family Anostostomatidae. Being a nocturnal species, individuals remain in tunnels in the ground during the day and emerge from their burrows after sunset to forage and hunt for small invertebrates. H. maculifrons is one of the smallest New Zealand weta species, averaging 15 mm in length and weighing 1–3 g. Unlike the tree weta and tusked weta, where sexual dimorphism is found in the form of male weaponry, ground weta only exhibit sexual size dimorphism: the females are larger than the males.
