Grouse are a group of birds from the order Galliformes, in the family Phasianidae. Grouse are presently assigned to the tribe Tetraonini, a classification supported by mitochondrial DNA sequence studies, and applied by the American Ornithologists' Union, ITIS, International Ornithological Congress, and others.
Sexual dimorphism is the condition where sexes of the same species exhibit different morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecious species, which consist of most animals and some plants. Differences may include secondary sex characteristics, size, weight, color, markings, or behavioral or cognitive traits. Male-male reproductive competition has evolved a diverse array of sexually dimorphic traits. Aggressive utility traits such as "battle" teeth and blunt heads reinforced as battering rams are used as weapons in aggressive interactions between rivals. Passive displays such as ornamental feathering or song-calling have also evolved mainly through sexual selection. These differences may be subtle or exaggerated and may be subjected to sexual selection and natural selection. The opposite of dimorphism is monomorphism, when both biological sexes are phenotypically indistinguishable from each other.
Waders or shorebirds are birds of the order Charadriiformes commonly found wading along shorelines and mudflats in order to forage for food crawling or burrowing in the mud and sand, usually small arthropods such as aquatic insects or crustaceans. The term "wader" is used in Europe, while "shorebird" is used in North America, where "wader" may be used instead to refer to long-legged wading birds such as storks and herons.
The Gerridae are a family of insects in the order Hemiptera, commonly known as water striders, water skeeters, water scooters, water bugs, pond skaters, water skippers, water gliders, water skimmers or puddle flies. Consistent with the classification of the Gerridae as true bugs, gerrids have mouthparts evolved for piercing and sucking, and distinguish themselves by having the unusual ability to walk on water, making them pleuston (surface-living) animals. They are anatomically built to transfer their weight to be able to run on top of the water's surface. As a result, one could likely find water striders present in any pond, river, or lake. Over 1,700 species of gerrids have been described, 10% of them being marine.
Veliidae is a family of gregarious predatory insects in the suborder Heteroptera. They are commonly known as riffle bugs, small water striders, or broad-shouldered water striders because the segment immediately behind the head is wider than the rest of the abdomen. Species of the genus Rhagovelia are also referred to as ripple bugs.
The raft spider, scientific name Dolomedes fimbriatus, is a large semi-aquatic spider of the family Pisauridae found throughout north-western and central Europe. It is one of only two species of the genus Dolomedes found in Europe, the other being the slightly larger Dolomedesplantarius which is endangered in the UK.
The tusked frog is a species of ground-dwelling frog native to eastern Australia from Eungella National Park, Queensland south to Ourimbah, New South Wales. It is the only species in the genus Adelotus - adelotus meaning "unseen" and brevis meaning "short".
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.
Nephila pilipes is a species of golden orb-web spider. It resides all over countries in East and Southeast Asia as well as Oceania. It is commonly found in primary and secondary forests and gardens. Females are large and grow to a body size of 30–50 mm, with males growing to 5–6 mm. It is the second largest of the orb-weaving spiders apart from the recently discovered Nephila komaci. The first, second, and fourth pairs of legs of juvenile females have dense hairy brushes, but these brushes disappear as the spider matures.
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. Sexual conflict underlies the evolutionary distinction between male and female.
The New Zealand giraffe weevil, Lasiorhynchus barbicornis, is a straight-snouted weevil in the subfamily Brentinae, endemic to New Zealand. L. barbicornis is New Zealand's longest beetle, and shows extreme sexual dimorphism: males measure up to 90mm, and females 50mm, although there is an extreme range of body sizes in both sexes. In males, the elongated snout can be nearly as long as the body. Male giraffe weevils use this long rostrum to battle over females, although small males can avoid conflict and 'sneak' in to mate with females, sometimes under the noses of large males. The larval weevils tunnel into wood for at least two years before emerging, and live for only a few weeks as adults.
Sexual dimorphism describes the morphological, physiological, and behavioral differences between males and females of the same species. Most primates are sexually dimorphic for different biological characteristics, such as body size, canine tooth size, craniofacial structure, skeletal dimensions, pelage color and markings, and vocalization. However, such sex differences are primarily limited to the anthropoid primates; most of the strepsirrhine primates and tarsiers are monomorphic.
Gerris lacustris, commonly known as the common pond skater or common water strider, is a species of water strider, found across Europe.
Aquarius remigis, known as the common water strider, is a species of aquatic bug. It was formerly known as Gerris remigis, but the subgenus Aquarius was elevated to generic rank in 1990 on the basis of phylogenetic analysis. Aquarius remigis is found throughout North America, but is most prevalent in the mid-west of the United States.
Aquarius najas, also known as the river skater, is a European species of water strider. It was formerly known as Gerris najas, but the subgenus Aquarius was elevated to generic rank in 1990 on the basis of phylogenetic analysis.
Gerrinae is a subfamily of water strider. This subfamily includes the largest and most best-known group of Gerridae. They are also a phylogenetic subfamily made up of two tribes, and ~14 genera.
Sexual selection in spiders shows how sexual selection explains the evolution of phenotypic traits in spiders. Male spiders have many complex courtship rituals and have to avoid being eaten by the females, with the males of most species surviving only a few matings and consequently having short life-spans.
Sexual coercion among 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.
Aquarius is a genus of water striders found predominantly in the northern hemisphere. Formerly a subgenus, Aquarius was elevated to generic rank in 1990 on the basis of phylogenetic analysis. These are among the world's largest water striders, with females averaging 12–17 mm (0.47–0.67 in) long and males roughly 10–30% smaller, depending on the exact species. An outlier is A. elongatus where both sexes typically are about 24 mm (0.94 in), roughly the same as certain Cylindrostethus, and second only to Gigantometra gigas.
Gerris buenoi is a species of water strider that belongs to the family Gerridae. It was first identified in 1911 and is native to continental USA and Canada. Individuals of this species are small in size and have modified appendages, allowing them to float and "skate" along the surface of the water. G. buenoi can be found near the shoreline of freshwater ponds and small lakes, where they hunt for terrestrial insects that have fallen into the water.
