Sex allocation in Telenomus busseolae, a solitary parasitoid of concealed eggs: the influence of host patch size |
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Authors: | Ahmet Bayram Gianandrea Salerno Eric Conti Eric Wajnberg Ferdinando Bin & Serpil Kornoor |
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Institution: | Department of Plant Protection, Faculty of Agricultural Sciences, Dicle University, 21280 Diyarbakir, Turkey;;Department of Arboriculture and Plant Protection-Entomology, University of Perugia, Borgo XX Giugno, 06121 Perugia, Italy;;INRA, 400 Route des Chappes, BP 167, 06 903 Sophia Antipolis Cedex, France;;Department of Plant Protection, Faculty of Agricultural Sciences, Cukurova University, 01330 Balcali-Adana, Turkey |
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Abstract: | Telenomus busseolae Gahan (Hymenoptera: Scelionidae) is an important egg parasitoid of noctuid stem borers of gramineous crops, attacking egg masses of Sesamia spp. Under natural conditions, and whatever the host species attacked, these egg masses are generally concealed under the leaf sheaths or other narrow spaces, and vary greatly in size. In the work presented here, the influence of host patch size (4, 8, 16, 32, 64, or 128 eggs per mass) on the sex ratio and sex sequence pattern of ovipositing T. busseolae was investigated in the laboratory using Sesamia nonagrioides (Lefebvre) (Lepidoptera: Noctuidae) as host. The results are similar to those described for other parasitoids of aggregated hosts, and are in accordance with the Local Mate Competition model. With increasing egg mass size, the overall sex ratio (proportion of males) decreased, although additional males were laid at the end of the sequence in the larger masses (64 and 128 eggs). Sex sequence pattern always followed a males‐first strategy, i.e., with a higher proportion of males at the beginning, but the whole sex ratio sequence was influenced by the size of the egg mass. Such results in a parasitoid of concealed eggs are compared to those observed in parasitoids of exposed eggs and discussed in terms of parasitoid reproductive strategies and evolutionary adaptations. |
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Keywords: | sex ratio Local Mate Competition male first strategy egg mass size oviposition sequence concealed hosts egg parasitoid Scelionidae Hymenoptera Lepidoptera Noctuidae |
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