TY - JOUR
T1 - Sex Ratios in a Socially Parasitic Bee and Implications for Host-Parasite Interactions
AU - Shokri Bousjein, Nahid
AU - Staines, Morgan
AU - Vo, Cathy
AU - Puiu, Natalie
AU - da Silva, Carmen
AU - Harrington, Jack
AU - Wilkinson, Sara
AU - Pratt, Kelly
AU - Schwarz, Michael
PY - 2017/1
Y1 - 2017/1
N2 - Obligate social parasites of Hymenoptera, known as inquilines, have received enormous attention due to the elaborate adaptations they exhibit for exploiting their hosts, and because they have frequently been used to infer sympatric speciation. Their population biology can be difficult to infer as they are both rare and difficult to extract from host nests. Sex allocation has been studied for very few inquilines of social Hymenoptera. Here we report sex ratio patterns in the allodapine bee Inquilina schwarzi, which is an obligate social parasite of another allodapine, Exoneura robusta. We show that the sex ratio of this inquiline varies with its brood number, it is female-biased in the smallest broods, but becomes more even in larger broods, where the population-wide sex ratio is close to parity. We argue that this pattern of bias is consistent with local resource competition, where inquiline females compete to inherit their natal colony. We also argue that extremely female-biased sex ratios of the host species, combined with overall sex ratio parity in the parasite, may help ameliorate disparity in effective population sizes between these two species which are locked in an evolutionary arms race.
AB - Obligate social parasites of Hymenoptera, known as inquilines, have received enormous attention due to the elaborate adaptations they exhibit for exploiting their hosts, and because they have frequently been used to infer sympatric speciation. Their population biology can be difficult to infer as they are both rare and difficult to extract from host nests. Sex allocation has been studied for very few inquilines of social Hymenoptera. Here we report sex ratio patterns in the allodapine bee Inquilina schwarzi, which is an obligate social parasite of another allodapine, Exoneura robusta. We show that the sex ratio of this inquiline varies with its brood number, it is female-biased in the smallest broods, but becomes more even in larger broods, where the population-wide sex ratio is close to parity. We argue that this pattern of bias is consistent with local resource competition, where inquiline females compete to inherit their natal colony. We also argue that extremely female-biased sex ratios of the host species, combined with overall sex ratio parity in the parasite, may help ameliorate disparity in effective population sizes between these two species which are locked in an evolutionary arms race.
KW - Bees
KW - effective population size
KW - inquilines
KW - local resource competition
KW - sex ratio
KW - social parasites
UR - http://www.scopus.com/inward/record.url?scp=85011860432&partnerID=8YFLogxK
U2 - 10.1007/s10905-017-9603-7
DO - 10.1007/s10905-017-9603-7
M3 - Article
VL - 30
SP - 130
EP - 137
JO - Journal of Insect Behavior
JF - Journal of Insect Behavior
SN - 0892-7553
IS - 1
ER -