Encountering competitors reduces clutch size and increases offspring size in a parasitoid with female-female fighting.
Understanding the size of clutches produced by only one parent may require a game-theoretic approach: clutch size may affect offspring fitness in terms of future competitive ability. If larger clutches generate smaller offspring and larger adults are more successful in acquiring and retaining resources, clutch size optima should be reduced when the probability of future competitive encounters is higher. We test this using Goniozus nephantidis, a gregarious parasitoid wasp in which the assumption of size-dependent resource acquisition is met via female-female contests for hosts. As predicted, smaller clutches are produced by mothers experiencing competition, due to fewer eggs being matured and to a reduced proportion of matured eggs being laid. As assumed, smaller clutches generate fewer but larger offspring. We believe this is the first direct evidence for pre-ovipositional and game-theoretic clutch size adjustment in response to an intergenerational fitness effect when clutches are produced by a single individual.
Goubault
Marlène
M
School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, UK.
Mack
Alexandra F S
AF
Hardy
Ian C W
IC
D000374:Aggression / Q000502:physiology*; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001835:Body Weight / Q000502:physiology*; D052284:Clutch Size / Q000502:physiology*; D005260:Female; D012098:Reproduction / Q000502:physiology; D014863:Wasps / Q000502:physiology*
Proc Biol Sci. 2002 Oct 7;269(1504):1989-92
12396497
Am Nat. 1998 May;151(5):409-24
18811316
J Anim Ecol. 2007 Mar;76(2):376-83
17302845
Proc Biol Sci. 2004 May 7;271(1542):971-8
15255053
Proc Biol Sci. 2006 Nov 22;273(1603):2853-9
17015315
Anim Behav. 2000 Jun;59(6):1111-1118
10877889