Eusociality and extraordinary sex ratios in the spider Anelosimus eximius (Araneae: Theridiidae)

@article{Vollrath2004EusocialityAE,
  title={Eusociality and extraordinary sex ratios in the spider Anelosimus eximius (Araneae: Theridiidae)},
  author={Fritz Vollrath},
  journal={Behavioral Ecology and Sociobiology},
  year={2004},
  volume={18},
  pages={283-287}
}
  • F. Vollrath
  • Published 1 February 1986
  • Biology
  • Behavioral Ecology and Sociobiology
SummaryColonies of Anelosimus eximius in Panama had an average sex ratio of 0.15±sd 0.09, i.e. about five females for each male. The sex ratio in egg sacs reared was even lower (0.08±0.01), as was that of immatures in newly founded colonies (0.12±0.05). The possible mechanisms responsible are discussed. Mature colonies had an average ratio of 17 females and 2 males for each egg sac present (range: 2–91 females, 0.2–8.2 males) and contained a large proportion of females which were not… 

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References

SHOWING 1-10 OF 41 REFERENCES

Sex-Ratio Bias and Possible Group Selection in the Social Spider Anelosimus eximius

TLDR
It is suggested that the unique population structure and dynamics of this social spider resulted in a change of balance between the opposing forces of group and individual selection, making evolutionarily stable a sex ratio that increases colony survival and proliferation.

Behaviour of colonial and solitary spiders of the theridiid species Anelosimus eximius

Social spiders catch larger prey: a study of Anelosimus eximius (Araneae: Theridiidae)

  • W. Nentwig
  • Biology
    Behavioral Ecology and Sociobiology
  • 2004
TLDR
Prey of the social theridiid Anelosimus eximius was analysed at two locations and compared with the potential prey spectrum according to sweepnet catches, pitfall traps and bowl traps, finding the ability to catch large prey insects is discussed as a major driving factor for sociality in spiders.

The Evolution of Eusociality in Termites: A Haplodiploid Analogy?

  • R. Lacy
  • Biology
    The American Naturalist
  • 1980
TLDR
It appears that a mechanism for the evolution of sterile castes in termites till must be sought.

EVOLUTION OF SEX RATIO IN STRUCTURED DEMES

In 1930 R. A. Fisher proposed an evolutionary model to explain why so many species produce roughly equal numbers of male and female offspring at birth. Very simply, since each offspring has a male

Evolution of Social Behavior in Spiders (Araneae; Eresidae and Theridiidae)

TLDR
The comparative study of the phylogeny of social behavior in both families uncovers remarkable convergences of patterns from asocial to permanent-social via periodical-social species of spiders.

Haploidploidy and the evolution of the social insect.

TLDR
Evidence is presented from 20 species that the ratio of investment in monogynous ants is, indeed, about 1 : 3, and this discovery is subject to a series of tests, which provide quantitative evidence in support of kinship theory, sex ratio theory, and the assumption that the offspring is capable of acting counter to its parents' best interests.

FEMALE‐BIASED SEX RATIOS IN SOCIAL INSECTS LACKING MORPHOLOGICAL CASTES

  • J. Strassmann
  • Biology
    Evolution; international journal of organic evolution
  • 1984
TLDR
In species of social insects in which workers are not morphologically distinct from queens, selection on optimum timing of worker versus reproductive production may result in both variable and female-biased sex ratios among reproductives.

Permanent segmental interchange complex in the termite Incisitermes schwarzi

TLDR
This report is concerned with the chromosomes of I. schwarzi, which has the most extensive complex of reciprocal translocations so far described in any animal species.

Prey caught by a sample population of the spider Argiope argentata (Araneae: Araneidae) in Panama: a year's census data

TLDR
The prey caught by mature female Argiope argentata was censused over a period of one year and the prey-animals seen in the webs were classified into orders and lower taxa, where possible.