TY - JOUR
T1 - Effects of time-dependent competition for oviposition sites on clutch sizes and offspring sex ratios in a fig wasp
AU - Kinoshita, Motoaki
AU - Kasuya, Eiiti
AU - Yahara, Tetsukazu
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2002
Y1 - 2002
N2 - Fig wasps have been known as one of the best-documented examples of female-biased sex ratio predicted from the local mate competition (LMC) theory. However, observed sex ratios appear more female-biased than predicted. Before a close match between theory and observation can be claimed, the number and sex ratio of offspring left by each foundress in a multi-foundress syconium need to be determined. We examined the clutch size and sex ratio of individual females of the pollinator fig wasp Blastophaga nipponica (Agaonidae) in experiments using a pair of fertile and sterile females in which sequence and time interval of entering syconia were manipulated. To determine the number and sex ratio of offspring left by each foundress in a multi-foundress syconium, we prepared sterilized females that could oviposit ordinarily but whose offspring could not develop at all, by irradiating the females with 60Co gamma rays. Female fig wasps contributed different numbers and sex ratios of offspring to the total brood within a syconium, due to different entry times among them. The variation in clutch sizes with different entry times appeared to be caused by competition for oviposition sites, and sex ratios to be adjusted according to the clutch size.
AB - Fig wasps have been known as one of the best-documented examples of female-biased sex ratio predicted from the local mate competition (LMC) theory. However, observed sex ratios appear more female-biased than predicted. Before a close match between theory and observation can be claimed, the number and sex ratio of offspring left by each foundress in a multi-foundress syconium need to be determined. We examined the clutch size and sex ratio of individual females of the pollinator fig wasp Blastophaga nipponica (Agaonidae) in experiments using a pair of fertile and sterile females in which sequence and time interval of entering syconia were manipulated. To determine the number and sex ratio of offspring left by each foundress in a multi-foundress syconium, we prepared sterilized females that could oviposit ordinarily but whose offspring could not develop at all, by irradiating the females with 60Co gamma rays. Female fig wasps contributed different numbers and sex ratios of offspring to the total brood within a syconium, due to different entry times among them. The variation in clutch sizes with different entry times appeared to be caused by competition for oviposition sites, and sex ratios to be adjusted according to the clutch size.
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U2 - 10.1034/j.1600-0706.2002.960103.x
DO - 10.1034/j.1600-0706.2002.960103.x
M3 - Article
AN - SCOPUS:0036112244
SN - 0030-1299
VL - 96
SP - 31
EP - 35
JO - Oikos
JF - Oikos
IS - 1
ER -