Trade-Off Between Fitness Gain and Cost Determines Profitability of a Peach Aphid Parasitoid.
Aphidius colemani (Viereck) (Hymenoptera: Aphidiidae) is commercially produced and utilized for biological control of peach aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae) on greenhouse crops in many countries. To provide knowledge for the evaluation of parasitoid-host interactions and development of effective mass rearing programs, we investigated how and why host age or size affected fitness gain in A. colemani We show that the parasitoid was significantly more likely to encounter larger hosts and that an encounter almost always triggered an attack attempt. However, the attack attempt did not proportionally translate into oviposition because larger aphids had greater ability to defend themselves and the parasitoid spent more time in handling larger aphids. The host age at parasitization had no effect on emergence rates and sex ratio of parasitoid progeny, suggesting that pupae and larvae have similar survival rate in hosts of different ages and/or the parasitoid females do not adjust sex allocation based on host size. When parasitizing mid-aged hosts, the parasitoid gained maximum fitness for their progeny in developmental period, body size, and parasitism. Taking all findings together, we suggest that parasitizing mid-aged green peach aphid nymphs is most profitable for A. colemani.
Institute of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North, New Zealand (diwaskhatri@gmail.com; X.Z.He@massey.ac.nz; q.wang@massey.ac.nz), and q.wang@massey.ac.nz.
Diwas
D
Khatri
Institute of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North, New Zealand (diwaskhatri@gmail.com; X.Z.He@massey.ac.nz; q.wang@massey.ac.nz), and.
Xiong Z
XZ
He
Institute of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North, New Zealand (diwaskhatri@gmail.com; X.Z.He@massey.ac.nz; q.wang@massey.ac.nz), and q.wang@massey.ac.nz.
Qiao
Q
Wang
D000818:Animals; D001042:Aphids / Q000254:growth & development / Q000469:parasitology*; D056084:Genetic Fitness; D006790:Host-Parasite Interactions; D007814:Larva / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D009758:Nymph / Q000254:growth & development / Q000469:parasitology; D010572:Pest Control, Biological; D000068239:Prunus persica / Q000254:growth & development; D011679:Pupa / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D014863:Wasps / Q000235:genetics / Q000254:growth & development / Q000502:physiology*
Aphidius colemani; behavior; body size; fitness gain rate; host defence