The Reproductive Tract of the Males of the Zoophytophagous Predator Brontocoris tabidus (Signoret) (Heteroptera: Pentatomidae) with Different Diets and Ages

Abstract

Abstract: Problem statement: Brontocoris tabidus (Signoret) (Heteroptera: Pentatomidae) is a common and important species for the biological control of defoliating Lepidoptera caterpillars. Although it has a predatory feeding habit, this species make use of plant resources, which are essential for the maintenance of its population in laboratory colonies as well as in the field during periods of prey shortage. Thus B. tabidus has been considered an obligate zoophytophagous insect. However the impact of the age and herbivory on the morphology of the reproductive organs has been poorly studied in predatory Pentatomidae. The morphology of the reproductive tract of B. tabidus males with different ages and fed on different diets were analyzed. Approach: Nymphs of B. tabidus were maintained in the field with or without plants and fed on T. molitor pupae without plant (T₁); T. molitor pupae and Eucalyptus cloeziana plants (T₂); T. molitor pupae and Eucalyptus urophylla plants (T₃) or T. molitor pupae and guava plants (Psidium guajava L.) (T₄). Adults of B. tabidus obtained from each treatment were sexed in the first day of their emergence and thirty-six pairs were formed per treatment. Ten males of B. tabidus 15 and 21 days old, obtained in each treatment were dissected and the reproductive tract submitted to histological analyses. The total area of the testes of B. tabidus was measured and the data were submitted to the variance analysis and means between treatments were compared by the test of Newman-Keuls (p = 0.05). Results: The inner genitalia of B. tabidus males had red color and the testes with six follicles. Males 15 days old presented larger testes when fed on E. cloeziana (0.94 mm²), E. urophylla (0.98 mm²) or only T. molitor pupae (0.99 mm²) than with guava plants (0.76 mm²). Twenty-one days old B. tabidus males presented testes with similar size, independent of the diet. The testes follicles of B. tabidus had larger amount of spermatozoa with all diets and ages showing that the spermatogenesis process was completed. The testes of this predator showed similar histological characteristics with all diets. Conclusion: The herbivory change the morphology of the reproductive tract of B. tabidus males in field conditions resulting in testes with different sizes, but it does not affect the histology of the reproductive organ of this predator. Therefore, the food type supplied to B. tabidus males does not affect the spermatogenesis process in this natural enemy.