摘要:

The biology of the plant bugLopidea nigrideais described, with particular focus on whether this red and black species can be considered aposematic.Lopideaindividuals were rejected after attack in 92 of 112 feeding trials involving three of their five most common arthropod predator species. Compared to another syntopic plant bug species,L. nigrideais aggregated in distribution, and individuals are sedentary in their basic daily habits. These life‐history features, coupled with the ability to survive most attacks by arthropod predators in the feeding trials, suggest thatL. nigrideais protected to some degree by an aposematic defence. HowL. nigrideamay acquire its distastefulness is discussed, with special attention to host plant relations inL. nigrideaand in the genusLopideaas a whol

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1990.tb01971.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

One of the predictions of the ‘good genes’ model of sexual selection is that reproductively successful males with well‐developed indicator traits should show smaller variances for non‐indicator traits, that are not directly associated with mating success, when compared to non‐breeding males and females. Thus sexual selection should reinforce stabilizing natural selection in reducing the variance in quantitative traits. This prediction is tested by analysing variation in eight morphological traits of breeding males, non‐breeding males, and females of pupfish(Cyprinodon pecosensis).Breeding males tended to be less variable than non‐breeding males for all principal component factors, and for all morphological traits except for depth, although these differences were statistically significant only for PC2, and PC5 and for pelvic fin length, number of pelvic fin rays and number of preopercular and preorbital pores. Similarly, breeding males tended to be less variable than females for all principal component factors and for all morphological traits except for number of preopercular pores. These differences were statistically significant for PC2, and for depth, pelvic fin length, number of preorbital pores and pectoral fin rays. The overall pattern of reduced variability in independent traits of breeding males revealed by principal component analysis is very consistent and highly significant (P<105). These results support the prediction of the ‘good genes’ model and show that reproductively active males are subject to more severe stabilizing selection for several quantitative traits than non‐breeding males and females. Thus sexual selection, through male‐male competition, female choice, or an interaction of both selective processes, results in stabilizing selection on quantitative

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1990.tb01972.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Ontogenetic colour changes are non‐reversible colour changes associated with normal progressive development of an individual of a species. This paper provides the first review of the evolutionary significance of this phenomenon in animals. Proximate mechanisms and environmental cues are briefly discussed and a conceptual framework for understanding the ultimate reasons for ontogenetic colour change is established. Changes in size, vulnerability, reproductive status, habitat and metabolism are often associated with ontogenetic colour change and can aid in understanding its adaptive significance. Neutral or non‐adaptive ontogenetic colour changes due to phylogenetic inertia and developmental constraints are also considered. Existing studies of ontogenetic colour changes in marine invertebrates, terrestrial invertebrates, fish, amphibians, reptiles, birds and mammals are discussed within this framework. A need is identified for more experimental tests of hypotheses for the significance of ontogenetic colour cha

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1990.tb01973.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

In seven species of plethodontid salamanders(Desmognathus ochrophaeus, Eurycea bislineata, Plethodon cinereus, Batrachoseps attenuatus, Hydromantes italicus, Thorius narisovalisandBolitoglossa subpalmata), absolute and relative volumes of the eye, the brain, major regions of the brain, and regions containing the major visual and visuomotor centres (i.e. thalamus, praetectum, tectum and tegmentum mesencephali), and the density and number of neurons in these regions were determined. The seven species range from moderately large to extremely small in body size and from the smallest to the largest genome sizes found in terrestrial salamanders.The following processes were observed in miniaturized salamanders with intermediate to large genome and cell sizes(Batrachoseps, Thorius)as compared to small and medium‐sized salamanders with small genome and cell sizes: (1) increase in the relative size of the brain, from 3.9 to 12.4% of head volume; (2) reduction in relative size of the ventricles from 10.9 to 5.8% of brain volume; (3) increase in relative volume of those brain regions containing the major visual and visuomotor centres from 29.2 to 37% of brain volume; (4) increase in volume of grey matter relative to white matter, from 33.2 to 44.4% of midbrain volume; (5) increase in volume of tectal relative to tegmental grey matter, from 54.8 to 76.8% of total midbrain volume; (6) increase in neuron packing density in the regions containing the visual centres, from 16 to 31.5%. Because of these compensatory processes,Thorius, the smallest species with a head 1/27 and a brain 1/9 the size of that of the largest one,Hydromantes, has 1/3 as many central visual neurons (58 000vs.187 000).Some of these processes found in miniaturized salamanders, such as increase in tectal cell density, also occur in large salamanders with very large genome and cell sizes, viz. inBolitoglossa(25%) andHydromantes(29%). Thus, increase in genome size and cell size seem to pose functional problems similar to miniaturization; both cases involve an increase in cell size relative to overall organismal structur

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1990.tb01974.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

The importance for reproductive isolation of species‐specific acoustic differences between closely relatedRibautodelphaxplanthopper species is tested by measuring responses to playbacks of both conspecific and heterospecific signals. Females respond to heterospecific male calls at about 80% of the conspecific response level, irrespective of the degree of cross‐insemination of the combination involved. In a combination involvingR. albostriatus, a taxonomically more distantly related species, female response levels are only 15–33% of the normal level. Study of the development of both female responsiveness and receptiveness shows that response levels correspond fairly well with insemination levels. Female heterospecific response is far too high to explain isolation between the species. Female answers to heterospecific males calls have normal response‐delay times and durations. When offered a two‐way choice between female playback calls, males significantly more often approach the conspecific call in almost all combinations tested. Offering only a heterospecific female signal induces males to call, but not to search. Males are capable of maintaining at least part of the sexual isolation by distinguishing between different female calls. This seems in conflict with the popular theory that the sex with the greater parental investment, here the female, should be exerting t

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1990.tb01975.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Book reviewed in this article:Evolution and the Fossil Record, edited by K. C. Allen and D. E. G. BriggsMass Extinctions: Processes and Evolution, edited by Stephen K. DonovanA Functional Biology of Clonal Animals, by Roger N. Hughes. “Functional Biology‘ Series, edited by Peter CalowCharles Darwin in Australia, by F. W. and J. M. Nich

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1990.tb01976.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY