|Legaspi, JR., Benjamin - STATE OF FLORIDA|
Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 4, 2004
Publication Date: December 1, 2004
Citation: Legaspi, J.C., Shapiro, J.P., Legaspi, Jr., B. 2004. Biochemical comparison of field and laboratory populations of Podisus maculiventris (Heteroptera: Pentatomidae) in Florida. Southwestern Entomologist. 29(4):301-302. Interpretive Summary: The spined soldier bug is an important beneficial insect because it exists naturally in a variety of agricultural systems where it feeds on insect pests. However, little is known about how much the insect eats under field conditions, and the effects of natural diet on its body functions. In contrast, laboratory research at the Center for Medical, Agricultural and Veterinary Entomology, USDA, ARS, has produced much information on the effects of diet on such factors as its body weight and fat storage. By collecting field insects and comparing them with laboratory specimens, we are able to infer its field diet. Field-collected insects weighed about the same as insects fed one prey item every 9 days laboratory. Protein and fat were also higher in laboratory insects. Fatty acid contents were different in insects collected in the laboratory versus the field, suggesting different types of food eaten. The low food consumption rate in the field indicates that the spined soldier bug usually has little food available under natural conditions, but also that it is able to survive despite having very little food to eat. When used as a biological control, this insect may survive through periods difficult periods and be in a position to attack pests when their numbers begin to increase.
Technical Abstract: Podisus maculiventris (Say) (Heteroptera: Pentatomidae) were collected from grape vineyards in Florida and compared body weights against laboratory-reared individuals subjected to controlled feeding regimens. Lipids, soluble and yolk protein, and fatty acid contents were measured and used to evaluate diet under field conditions. Results showed that laboratory females (85 mg) were significantly heavier than males (57 mg). Field-collected females had live body weights comparable to laboratory females fed one prey item every 9 days. Laboratory-reared females were significantly heavier than field-collected females. Total soluble protein and total lipid contents were highest in female colony-reared insects; reflecting larger size of the colony-reared females, and their accumulation of nutrients and incorporation into developing eggs. Colony-reared females contained 37% more soluble protein (9.5 vs. 6.9 mg/insect) and 74% more lipid (59.4 vs. 34.1 mg/insect). Colony-reared females contained slightly more yolk protein than field-captured females. Four fatty acid methyl esters derivatives significantly differed in percent of total between colony-reared and field-collected insects, perhaps indicating differences in food sources in field versus laboratory environments.