TY - JOUR
T1 - Perceived risk of sperm competition affects juvenile development and ejaculate expenditure in male praying mantids
AU - Allen, Louise E.
AU - Barry, Katherine L.
AU - Holwell, Gregory I.
AU - Herberstein, Marie E.
PY - 2011/11
Y1 - 2011/11
N2 - Sperm competition occurs when a female mates with more than one male, and the sperm of those males compete directly over fertilizing her eggs. In polyandrous animals, males can respond to the perceived risk of sperm competition by flexibly adjusting aspects of their development and reproductive investment. In high-risk scenarios we might expect males to accelerate development so as to mature quickly and locate receptive females first and/or transfer more sperm so as to outcompete rival sperm. We examined these predictions using the false garden mantid, Pseudomantis albofimbriata, a medium-sized praying mantid found on the east coast of Australia. Males are less than half the mass of females. Sexual cannibalism occurs in up to 40% of interactions, highlighting the importance of investing optimally in reproductive opportunities for males. We housed juvenile males in two operational sex ratio treatments: three males, one female (high risk of sperm competition) and one male, three females (low risk). We found no evidence of accelerated development in the high-risk group; instead, high-risk males took longer to mature. Possibly, males exposed to a higher risk of sperm competition delay maturity in order to invest in testes development and sperm production. We also found that males reared in the high-risk treatment transferred significantly more sperm than males reared in the low-risk treatment, providing evidence of strategic ejaculation in male P. albofimbriata. This is the first study demonstrating a male response to the perceived risk of sperm competition via delayed development and increased ejaculate investment in praying mantids.
AB - Sperm competition occurs when a female mates with more than one male, and the sperm of those males compete directly over fertilizing her eggs. In polyandrous animals, males can respond to the perceived risk of sperm competition by flexibly adjusting aspects of their development and reproductive investment. In high-risk scenarios we might expect males to accelerate development so as to mature quickly and locate receptive females first and/or transfer more sperm so as to outcompete rival sperm. We examined these predictions using the false garden mantid, Pseudomantis albofimbriata, a medium-sized praying mantid found on the east coast of Australia. Males are less than half the mass of females. Sexual cannibalism occurs in up to 40% of interactions, highlighting the importance of investing optimally in reproductive opportunities for males. We housed juvenile males in two operational sex ratio treatments: three males, one female (high risk of sperm competition) and one male, three females (low risk). We found no evidence of accelerated development in the high-risk group; instead, high-risk males took longer to mature. Possibly, males exposed to a higher risk of sperm competition delay maturity in order to invest in testes development and sperm production. We also found that males reared in the high-risk treatment transferred significantly more sperm than males reared in the low-risk treatment, providing evidence of strategic ejaculation in male P. albofimbriata. This is the first study demonstrating a male response to the perceived risk of sperm competition via delayed development and increased ejaculate investment in praying mantids.
UR - http://www.scopus.com/inward/record.url?scp=80054757842&partnerID=8YFLogxK
U2 - 10.1016/j.anbehav.2011.09.009
DO - 10.1016/j.anbehav.2011.09.009
M3 - Article
AN - SCOPUS:80054757842
SN - 0003-3472
VL - 82
SP - 1201
EP - 1206
JO - Animal Behaviour
JF - Animal Behaviour
IS - 5
ER -