Altered trait variability in response to size-selective mortality

Changes in trait variability owing to size-selective harvesting have received little attention in comparison with changes in mean trait values, perhaps because of the expectation that phenotypic variability should generally be eroded by directional selection typical for fishing and hunting. We show, however, that directional selection, in particular for large body size, leads to increased body-size variation in experimentally harvested zebrafish ( Danio rerio ) populations exposed to two alternative feeding environments: ad libitum and temporarily restricted food availability. Trait variation may influence population adaptivity, stability and resilience. Therefore, rather than exerting selection pressures that favour small individuals, our results stress the importance of protecting large ones, as they can harbour a great amount of variation within a population, to manage fish stocks sustainably.

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Independent evolution towards larger body size in the distinctive Faroe Island mice

G3 Genes|Genome|Genetics ◽

10.1093/g3journal/jkaa051 ◽

2021 ◽

Author(s):

Ricardo Wilches ◽

William H Beluch ◽

Ellen McConnell ◽

Diethard Tautz ◽

Yingguang Frank Chan

Keyword(s):

Body Size ◽

Meta Analysis ◽

Small Body ◽

Laboratory Mouse ◽

Large Body ◽

Natural Populations ◽

Size Variation ◽

Phenotypic Traits ◽

Island Population ◽

Multiple Loci

Abstract Most phenotypic traits in nature involve the collective action of many genes. Traits that evolve repeatedly are particularly useful for understanding how selection may act on changing trait values. In mice, large body size has evolved repeatedly on islands and under artificial selection in the laboratory. Identifying the loci and genes involved in this process may shed light on the evolution of complex, polygenic traits. Here, we have mapped the genetic basis of body size variation by making a genetic cross between mice from the Faroe Islands, which are among the largest and most distinctive natural populations of mice in the world, and a laboratory mouse strain selected for small body size, SM/J. Using this F2 intercross of 841 animals, we have identified 111 loci controlling various aspects of body size, weight and growth hormone levels. By comparing against other studies, including the use of a joint meta-analysis, we found that the loci involved in the evolution of large size in the Faroese mice were largely independent from those of a different island population or other laboratory strains. We hypothesize that colonization bottleneck, historical hybridization, or the redundancy between multiple loci have resulted in the Faroese mice achieving an outwardly similar phenotype through a distinct evolutionary path.

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Prey preference of a wasp determined by nest size supports the role of natural selection in body size evolution in Cassidinae leaf beetles

Biological Journal of the Linnean Society ◽

10.1093/biolinnean/blab135 ◽

2021 ◽

Author(s):

Tadashi Shinohara ◽

Yasuoki Takami

Keyword(s):

Body Size ◽

Natural Selection ◽

Prey Species ◽

Large Body ◽

Size Variation ◽

Prey Preference ◽

Nest Size ◽

Large Prey ◽

Leaf Beetles ◽

Body Sizes

Abstract The prey preference of a predator can impose natural selection on prey phenotypes, including body size. Despite evidence that large body size protects against predation in insects, the determinants of body size variation in Cassidinae leaf beetles are not well understood. We examined the prey preference of the digger wasp Cerceris albofasciata, a specialist predator of adult Cassidinae leaf beetles, and found evidence for natural selection on prey body size. The wasp hunted prey smaller than the size of their nest entrance. However, the wasp preferred larger prey species among those that could be carried into their nest. Thus, the benefits of large prey and the cost associated with nest expansion might determine the prey size preference. As expected from the prey species preference, the wasp preferred small individuals of the largest prey species, Thlaspida biramosa, and large individuals of the smallest prey species, Cassida piperata, resulting in natural selection on body sizes. In intermediate-sized prey species, however, there was no evidence for selection on body size. Natural selection on body size might explain the variation of prey morphologies that increase body size, such as explanate margins, in this group.

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The effects of temperature change and domestication on the body size of Late Pleistocene to Holocene mammals of Israel

Paleobiology ◽

10.1017/s0094837300003821 ◽

1981 ◽

Vol 7 (1) ◽

pp. 101-114 ◽

Cited By ~ 111

Author(s):

Simon J. M. Davis

Keyword(s):

Body Size ◽

Temperature Change ◽

Late Pleistocene ◽

Eastern Mediterranean ◽

Large Body ◽

Size Variation ◽

The Body ◽

Main Body ◽

Fossil Species ◽

Late Pleistocene To Holocene

Size variation among several species of large mammals is examined both throughout a wide geographical range today and within the Late Pleistocene-Holocene archaeo-faunal sequence of Israel. A regression of log dental size on environmental temperature produces similar negative slopes for recent Palaearctic foxes, wolves and boars as well as for Nearctic foxes. These species, and others which also exhibit an inverse correlation between size and temperature today, became dwarfed at the end of the Pleistocene in Israel. Abundant fossil gazelle and fox mensural data indicate that this diminution coincided with the temperature elevation 12,000 yr ago. Both the similarity of regression slopes for the recent material and the temporal coincidence of dwarfing among fossil species, representing different ecologies, strongly implicate temperature as the main body-size determining factor. Changes evidenced in the fossil record for boar, wolf and fox approximate a 15°C temperature change (Δt) based on their respective present-day size-temperature regressions. This Δt, if taken as an estimate for the eastern Mediterranean, is considerably higher than generally accepted values.An additional size reduction of aurochs, wolf and boar at the end of the Pleistocene or several millenia later is associated with their domestication. It may reflect man's preference for a large “head count” over individual large body size.

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Large body size variation is linked to low communication success in tandem running ants

10.1101/789834 ◽

2019 ◽

Author(s):

Wagner Thomas ◽

Bachenberg Lena ◽

Glaser Simone ◽

Oikonomou Avgousta ◽

Linn Melissa ◽

...

Keyword(s):

Body Size ◽

Group Performance ◽

Large Body ◽

Size Variation ◽

Recruitment Strategy ◽

Size Difference ◽

Phenotypic Trait ◽

Negative Effects ◽

Tandem Running ◽

Communication Processes

AbstractDiversity in animal groups is often assumed to increase group performance. In insect colonies, genetic, behavioral and morphological variation among workers can improve colony functioning and resilience. However, it has been hypothesized that during communication processes, differences between workers, e.g. in body size, could also have negative effects. Tandem running is a common recruitment strategy in ants and allows a leader to guide a nestmate follower to resources. A substantial proportion of tandem runs fail because leader and follower loose contact. Using the ant Temnothorax nylanderi as a model system, we tested the hypothesis that tandem running success is impaired if leader and follower differ in size. Indeed, we found that the success rate of tandem pairs drops considerably as size variation increases: only ~7% of tandem runs were successful when the leader-follower size difference exceeded 10%, whereas 80% of tandem runs were successful when ants differed less than 5% in body length. One possible explanation is that ant size is linked to the preferred walking speed. Ants did not choose partners of similar size, but extranidal workers were larger than intranidal workers, which could reduce recruitment mistakes because it reduced the chance that very large and very small ants perform tandem runs together. Our results suggest that phenotypic differences between interacting workers can have negative effects on the efficiency of communication processes. Whether phenotypic variation has positive or negative effects is likely to depend on the task and the phenotypic trait that shows variation.

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Independent evolution towards large body size in the distinctive Faroe Island mice

10.1101/747097 ◽

2019 ◽

Author(s):

Ricardo Wilches ◽

William H. Beluch ◽

Ellen McConnell ◽

Diethard Tautz ◽

Yingguang Frank Chan

Keyword(s):

Body Size ◽

Meta Analysis ◽

Small Body ◽

Laboratory Mouse ◽

Large Body ◽

Size Variation ◽

Island Population ◽

Large Body Size ◽

Multiple Loci ◽

Similar Phenotype

AbstractMost traits in nature involve the collective action of many genes. Traits that evolve repeatedly are particularly revealing about how selection may act on traits. In mice, large body size has evolved repeatedly on islands and under artificial selection in the laboratory. Identifying the loci and genes involved in this process may shed light on the evolution of complex, polygenic traits. Here, we have mapped the genetic basis of body size variation by making a genetic cross between mice from the Faroe Islands, which are among the largest and most distinctive populations of mice in the world, and a laboratory mouse strain selected for small body size, SM/J. Using this F2 intercross of 841 animals, we have identified 102 loci controlling various aspects of body size, weight and growth hormone levels. By comparing against other studies, including the use of a joint meta-analysis, we found that the loci involved in the evolution of large size in the Faroese mice were largely independent from those of a different island population or other laboratory strains. We conclude that colonization bottleneck, historical hybridization, or the redundancy between multiple loci have resulted in the Faroese mice achieving an outwardly similar phenotype through a distinct evolutionary path.

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A new species of the subgenus Scheloribates (Topobates) (Acari: Oribatida: Scheloribatidae) from Panama

Zoosystematica Rossica ◽

10.31610/zsr/2020.29.2.278 ◽

2020 ◽

Vol 29 (2) ◽

pp. 278-283

Author(s):

S.G. Ermilov

Keyword(s):

New Species ◽

Body Size ◽

Leaf Litter ◽

Related Species ◽

Large Body ◽

Oribatid Mite ◽

Neotropical Region ◽

Large Body Size ◽

First Time ◽

A New Species

The oribatid mite subgenus Scheloribates (Topobates) Grandjean, 1958, is recorded from the Neotropical region for the first time. A new species of this subgenus is described from the leaf litter collected in Cayo Agua Island, Panama. Scheloribates (Topobates) panamaensis sp. nov. differs from its related species by the very large body size and presence of a strong ventrodistal process on the leg femora II–IV.

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APPARENT DIRECTIONAL SELECTION OF BODY SIZE INDROSOPHILA BUZZATII: LARVAL CROWDING AND MALE MATING SUCCESS

Evolution ◽

10.1111/j.1558-5646.1996.tb03641.x ◽

1996 ◽

Vol 50 (6) ◽

pp. 2530-2535

Author(s):

Mauro Santos

Keyword(s):

Body Size ◽

Mating Success ◽

Directional Selection ◽

Male Mating ◽

Male Mating Success ◽

Larval Crowding ◽

Selection Of

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Mammalian body size is determined by interactions between climate, urbanization, and ecological traits

Communications Biology ◽

10.1038/s42003-021-02505-3 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Maggie M. Hantak ◽

Bryan S. McLean ◽

Daijiang Li ◽

Robert P. Guralnick

Keyword(s):

Body Size ◽

Resource Availability ◽

Critical Role ◽

Size Variation ◽

Ecological Factors ◽

Species Traits ◽

Body Size Variation ◽

Resource Availability Hypothesis ◽

Urban Heat ◽

Thermal Buffering

AbstractAnthropogenically-driven climate warming is a hypothesized driver of animal body size reductions. Less understood are effects of other human-caused disturbances on body size, such as urbanization. We compiled 140,499 body size records of over 100 North American mammals to test how climate and human population density, a proxy for urbanization, and their interactions with species traits, impact body size. We tested three hypotheses of body size variation across urbanization gradients: urban heat island effects, habitat fragmentation, and resource availability. Our results demonstrate that both urbanization and temperature influence mammalian body size variation, most often leading to larger individuals, thus supporting the resource availability hypothesis. In addition, life history and other ecological factors play a critical role in mediating the effects of climate and urbanization on body size. Larger mammals and species that utilize thermal buffering are more sensitive to warmer temperatures, while flexibility in activity time appears to be advantageous in urbanized areas. This work highlights the value of using digitized, natural history data to track how human disturbance drives morphological variation.

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