Sexual dimorphism in immune response: Testing the hypothesis in an insect species with two male morphs |
| |
Authors: | Gloria Ruiz‐Guzmán Jorge Canales‐Lazcano Jesús Guillermo Jiménez‐Cortés Jorge Contreras‐Garduño |
| |
Institution: | 1. Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, , C. P. 62100 Cuernavaca, Morelos;2. Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, , Guanajuato;3. Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, , 04510 México, D. F., México |
| |
Abstract: | It has been proposed that given that males should invest in sexual traits at the expense of their investment in immune response, females are better immunocompetent than males. Typically, this idea has been tested in monomorphic species, but rarely has been evaluated in polymorphic male species. We used Paraphlebia zoe, a damselfly with two male morphs: the black‐winged morph (Black‐W) develop black spots as sexual traits and the hyaline‐winged morph (Hyaline‐W) resembles a female in size and wings color. We predicted that Black‐W should have a lower immune response than Hyaline‐W, but that the latter males should not differ from females in this respect. Nitric oxide (NO) and phenoloxidase (PO) production, as well as hemolymph protein content, were used as immune markers. Body size (wing length) was used as an indicator of the male condition. The results show that, as we predicted, females and Hyaline‐W had higher values of NO than Black‐W, corresponding to differences in size. However, the opposite was found in relation to PO production. Females had the highest levels of hemolymph protein content, whereas no differences were found between Black‐W and Hyaline‐W. These results partially support the sexual selection hypothesis and are discussed in the context of the life history of this species. Black‐W, Hyaline‐W, and females could express the immune markers that are prioritized by their particular condition, and probably neither of them could express all immune markers in an elevated manner, as this would result in an excessive accumulation of free radicals. |
| |
Keywords: | immune response male morphs Paraphlebia zoe polymorphic species territoriality trade‐off |
|
|