The parasitoid wasp genus Achrysocharoides (Eulophidae) is unusual in that many of
its species lay male and female eggs in single-sex clutches. The
average clutch size of female broods is always greater than that of
male broods, and in some species male clutch size is always one. We
constructed models that predicted that severely egg-limited wasps
should produce equal numbers of male and female eggs while severely
host-limited wasps should produce equal numbers of male and female broods
(and hence an overall female-biased sex ratio). Theory is developed
to predict clutch size and sex ratio across the complete spectrum
of host and egg limitation. A comparison of 19 surveys of clutch
composition in seven species of Achrysocharoides showed a general
pattern of equal numbers of male and female broods with a female-biased
sex ratio (suggesting host limitation) although with considerable
heterogeneity amongst collections and with a number of cases of unexpectedly
low frequencies of male broods. Using a previous estimate of the
relationship between fitness and size in the field, we predicted
the maximally productive (Lack) clutch size for female broods of
Achrysocharoides zwoelferi to be three. Of clutches observed in nature,
95% were equal to or smaller in size than the predicted Lack clutch
size. When we manipulated local host density in the field, and as
predicted by our models, clutch size and the proportion of female
broods of A. zwoelferi decreased as hosts became more common, but
the absolute frequency of male clutches was lower than expected.
%0 Journal Article
%1 West1999
%A West, S.A.
%A Flanagan, K.E.
%A Godfray, H.C.J.
%D 1999
%J Animal Behaviour
%K ER limitation;
%N 2
%P 265-275
%T Sex allocation and clutch size in parasitoid wasps that produce single-sex broods
%V 57
%X The parasitoid wasp genus Achrysocharoides (Eulophidae) is unusual in that many of
its species lay male and female eggs in single-sex clutches. The
average clutch size of female broods is always greater than that of
male broods, and in some species male clutch size is always one. We
constructed models that predicted that severely egg-limited wasps
should produce equal numbers of male and female eggs while severely
host-limited wasps should produce equal numbers of male and female broods
(and hence an overall female-biased sex ratio). Theory is developed
to predict clutch size and sex ratio across the complete spectrum
of host and egg limitation. A comparison of 19 surveys of clutch
composition in seven species of Achrysocharoides showed a general
pattern of equal numbers of male and female broods with a female-biased
sex ratio (suggesting host limitation) although with considerable
heterogeneity amongst collections and with a number of cases of unexpectedly
low frequencies of male broods. Using a previous estimate of the
relationship between fitness and size in the field, we predicted
the maximally productive (Lack) clutch size for female broods of
Achrysocharoides zwoelferi to be three. Of clutches observed in nature,
95% were equal to or smaller in size than the predicted Lack clutch
size. When we manipulated local host density in the field, and as
predicted by our models, clutch size and the proportion of female
broods of A. zwoelferi decreased as hosts became more common, but
the absolute frequency of male clutches was lower than expected.
@article{West1999,
abstract = {The parasitoid wasp genus Achrysocharoides (Eulophidae) is unusual in that many of
its species lay male and female eggs in single-sex clutches. The
average clutch size of female broods is always greater than that of
male broods, and in some species male clutch size is always one. We
constructed models that predicted that severely egg-limited wasps
should produce equal numbers of male and female eggs while severely
host-limited wasps should produce equal numbers of male and female broods
(and hence an overall female-biased sex ratio). Theory is developed
to predict clutch size and sex ratio across the complete spectrum
of host and egg limitation. A comparison of 19 surveys of clutch
composition in seven species of Achrysocharoides showed a general
pattern of equal numbers of male and female broods with a female-biased
sex ratio (suggesting host limitation) although with considerable
heterogeneity amongst collections and with a number of cases of unexpectedly
low frequencies of male broods. Using a previous estimate of the
relationship between fitness and size in the field, we predicted
the maximally productive (Lack) clutch size for female broods of
Achrysocharoides zwoelferi to be three. Of clutches observed in nature,
95% were equal to or smaller in size than the predicted Lack clutch
size. When we manipulated local host density in the field, and as
predicted by our models, clutch size and the proportion of female
broods of A. zwoelferi decreased as hosts became more common, but
the absolute frequency of male clutches was lower than expected.},
added-at = {2009-12-02T17:49:46.000+0100},
author = {West, S.A. and Flanagan, K.E. and Godfray, H.C.J.},
biburl = {https://www.bibsonomy.org/bibtex/273f6acc62ee73c850b6637d44225a702/embeh},
interhash = {f9533494b04eedea2420d727abbdf558},
intrahash = {73f6acc62ee73c850b6637d44225a702},
journal = {Animal Behaviour},
keywords = {ER limitation;},
number = 2,
owner = {oliver},
pages = {265-275},
timestamp = {2009-12-02T17:50:18.000+0100},
title = {Sex allocation and clutch size in parasitoid wasps that produce single-sex broods},
volume = 57,
year = 1999
}