Do mbuna have teeth?

Is there a phylogenetic analysis of sexual dimorphism in pinnipeds?

“Phylogenetic analyses of sexual selection and sexual size dimorphism in pinnipeds”. Behavioral Ecology and Sociobiology. 52 (3): 188–193. doi: 10.1007/s00265-002-0507-x.

What is the relationship between size dimorphism and cannibalism in wolf spiders?

Size dimorphism shows a correlation with sexual cannibalism, which is prominent in spiders (it is also found in insects such as praying mantises ). In the size dimorphic wolf spider, food-limited females cannibalize more frequently. Therefore, there is a high risk of low fitness for males due to pre-copulatory…

What is an example of sexual size dimorphism?

The female-biased sexual size dimorphism observed in many taxa evolved despite intense male–male competition for mates. In Osmia rufa, for example, the female is larger/broader than males, with males being 8–10 mm in size and females being 10–12 mm in size.

Does size dimorphism increase with body size in insects?

^ Teder, T., & Tammaru, T. (2005). Sexual size dimorphism within species increases with body size in insects. Oikos ^ Oliver JC, Monteiro A (July 2011).

What are the differences between the sexes of pinnipeds?

Differences between the sexes may occur in the size and shape of the head, teeth, thoracic girth, flukes, flippers, dorsal fin, caudal peduncle, postanal hump, and length of the beak. The 36 species of pinnipeds show the greatest range in sexual size dimorphism of any higher vertebrate group.

How do pinnipeds differ in size dimorphism?

The 36 species of pinnipeds show the greatest range in sexual size dimorphism of any higher vertebrate group. Adult males are up to 10 times as heavy as adult females in some species, whereas females are slightly larger than males in others. The variation in sexual dimorphism among marine mammal taxa is striking.

Is there a diphyletic origin of pinnipeds?

A diphyletic origin of pinnipeds serves as a compelling argument to explain the contrasting swimming styles and morphological disparity observed between otariids and phocids ( Kuhn and Frey, 2012 ).

Are there any animals that have sexual dimorphism in genital pigment patterns?

Sexual dimorphism in genital pigment patterns is known in several species [killer whales, dolphins in the genus Cephalorhynchus and Lissodelphis, shortbeaked common dolphins (Delphinus delphis), Burmeister’s porpoises (P. spinipinnis), and Dall’s porpoises].

What are some examples of dimorphism in taxa?

Sexual size dimorphism varies among taxa with males typically being larger, though this is not always the case, e.g. birds of prey, hummingbirds, and some species of flightless birds. Plumage dimorphism, in the form of ornamentation or coloration, also varies, though males are typically the more ornamented or brightly colored sex.

Why do tracheae increase in size as insects grow?

As insects increase in size, tracheae take up a proportionally greater amount of space in their bodies because they need to increase in length and width to deliver oxygen as a larger body size increases oxygen needs. This inhibits growth because at a certain point the tracheae become impractical and crowd other organs (Kirkton 2007).

How are insects limited by their size?

In either scenario, the primitive land-bound insect is limited by size because of its exoskeleton and tracheal system. If for some reason the insect first has no reason to evolve an exoskeleton-perhaps it is small enough or evasive enough to avoid prying predators – then it would be limited by its tracheal system.

Why did insects get smaller?

When insect size did decrease, this event coincided first with the evolution of birds, and then again with that of bats. With predatory birds in the air, the need for maneuverability and evasiveness trumped the evolutionary drive to be big, and insects decreased in size.

What happens to an ant’s exoskeleton as its size increases?

For example, if an ant’s exoskeleton must become thicker as body size increases (strength is proportional to length squared whereas mass is proportional to length cubed), at a certain point this thickness would cause the ant’s legs to crumple under the strain of holding up its own body weight.

Do fishing spiders (Dolomedes triton) have sexual cannibalism?

Sexual cannibalism in fishing spiders (Dolomedes triton): An evaluation of two explanations for female aggression towards potential mates. Anim Behav 61: 905–914.

Are one-palped spiders monogynous?

The mating system of these one-palped spiders can be safely considered monogynous, although natural mating rates of females are unknown for all these species ( Knoflach and van Harten 2001 ).

Is the brown widow spider (Latrodectus geometricus) a cannibal?

Sexual cannibalism in the brown widow spider (Latrodectus geometricus). Ethology 114: 279–286. [ Google Scholar] Sentenska L, Pekar S 2013. Mate with the young, kill the old: Reversed sexual cannibalism and male mate choice in the spider Micaria sociabilis (Araneae: Gnaphosidae).

Is the fishing spider a model of sexual cannibalism?

Sexual cannibalism in the fishing spider and a model for the evolution of sexual cannibalism based on genetic constraints. Evol Ecol 11: 255–273.

What is an example of sexual dimorphism?

Sexual dimorphism in humans rarely experience sexual ambiguity, but when it does, the individual is biologically identified as intersex. The gonads, breasts, external genitals, internal genitals, body mass, the endocrine systems, height, and their physiological and behavioural effects are all examples of sexual dimorphism in humans.

What type of animal is a pinniped?

Pinnipeds (pronounced / ˈpɪnɪˌpɛdz / ), commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin -footed, semiaquatic, mostly marine mammals.

What is the distribution of pinnipeds?

This species has a discontinuous distribution around the Arctic Circle. Living pinnipeds mainly inhabit polar and subpolar regions, particularly the North Atlantic, the North Pacific and the Southern Ocean. They are entirely absent from Indomalayan waters. Monk seals and some otariids live in tropical and subtropical waters.

What is the difference between a walrus and a pinniped?

The walrus has unique upper canines that are elongated into tusks. The mammary glands and genitals of pinnipeds can retract into the body. Pinnipeds range in size from the 1 m (3 ft 3 in) and 45 kg (99 lb) Baikal seal to the 5 m (16 ft) and 3,200 kg (7,100 lb) southern elephant seal.

What are the physical characteristics of human sexual dimorphism?

As per Clark Spencer Larsen, modern Homo sapiens exhibit a wide spectrum of human sexual dimorphism, with about 15 percent average body mass differences between individual sexes. In adolescent males, the mean basal metabolic rate has been approximately 6% higher than those in females, and it rises to almost 10% greater following puberty.

What is sexual dimorphism?

e Sexual dimorphism is the condition where the two sexes of the same species exhibit different characteristics beyond the differences in their sexual organs. The condition occurs in most animals and some plants.

Are pinnipeds related to dogs and bears?

Pinnipeds (seals, sea lions, and walruses) are a group of marine carnivores related to dogs, bears, and weasels. Three extant and one extinct family of pinnipeds exist; these include eared seals (aka fur seals and sea lions; Otariidae), walruses (Odobenidae), true or hair seals (Phocidae), and the extinct pseudo-seals (Desmatophocidae).