Submitted to: Entomology Society Of America Annals
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 12, 1996
Publication Date: N/A
Interpretive Summary: Augmentative releases of the parasitic wasp, Catolaccus grandis, have proven successful in controlling the boll weevil in cotton fields in the Rio Grande Valley. The methods of mass propagation and release of this wasp have been developed to a significant extent. However, information about the nutrition of the adult wasp is limited at present. This knowledge is important to understand the minimal requirements for the survival of these natural enemies in the field and to enhance the quality of the adults released. This study provides answers to those questions. Results showed that females of C. grandis require sugars to survive. Sugar solutions of 30% fructose adn glucose (1:1) were adequate to prolong life in the adult wasps. Feeding on host haemolymph (blood) in the absence of sugar did not improve survival of adult wasps as compared to feeding them only water. Nutrition of the adult wasps was not the most important factor renhancing reproduction. The detection of host by contact increased the reproductive capacity of C. grandis females by 4 fold. This study concludes that a sugar (as nectaries) is essential to maintain adult wasps alive in the field. The presence of host in the field does not warranty the survival of adult C. grandis. The release of females with oviposition experience of at least 2 days is recommended.
Technical Abstract: The effect of different concentrations of fructose and glucose on the longevity of the boll weevil (Anthonomus grandis Boheman) ectoparasitoid Catolaccus grandis (Burks) was tested. Sugar concentrations of 30% significantly increased longevity compared to 50 and 70% sugar solutions. Longevity was not significantly improved when boll weevil larvae were provided as a source of host-feeding. In the absence of a carbohydrate source, host-feeding was ineffective for maintaining C. grandis alive for more than 2.5 d. Providing adult C. grandis females with diets supplemented with amino acids and boll weevil haemolymph did not induce oogenesis. Females with oviposition experience produced 4 times as many eggs as inexperienced females regardless of quality of the adult diet provided. However, adult nutrition was important for egg production after oogenesis was initiated. Experienced C. grandis females produced significantly more eggs when a supplemental diet was provided in the absence of host-feeding opportunities.