Temporal Dynamics of Flight Muscle Development in Triatoma infestans (Hemiptera: Reduviidae)

• Published in: Journal of medical entomology Vol. 46; no. 5; pp. 1021 - 1024
• Main Authors: Gurevitz, Juan M, Kitron, Uriel, Gurtler, Ricardo E
• Format: Journal Article
• Language: English
• Published: England 01.09.2009
• Subjects: adult insects; Animals; Argentina; disease transmission; dispersal behavior; ecdysis; eclosion; Female; females; flight; flight muscles; Flight, Animal; gender differences; insect anatomy; insect behavior; insect development; insect morphology; insect pests; insect vectors; Male; males; mortality; Muscle Development; nymphs; organogenesis; thorax; Time Factors; Triatoma - growth & development; Triatoma infestans; Argentina
• ISSN: 0022-2585; 1938-2928
• DOI: 10.1603/033.046.0507

Triatoma infestans Klug is dimorphic for flight muscles. This dimorphism may affect flight dispersal, reinfestation patterns, and transmission risk. To understand the contributions of genes and environment to morph determination, it is first necessary to characterize the temporal dynamics of flight muscle development. Field-collected T. infestans adults were dissected 20 or 100 d after collection, and those collected as nymphs were dissected at approximately equal to 4, 15, or 44 d after the imaginal molt. The occurrence of flight muscles was additionally assessed by minimally invasive, repeated observations through the scutum of live bugs. Overall, 33.5% of 179 males and 7.8% of 179 females had no flight muscles. Neither dissections nor repeated observations evidenced changes in morph type during adult life, suggesting that the occurrence of flight muscles is mostly irreversible within the time span of observations and is determined before or during final ecdysis. Flight muscles were detectable at 4 d after emergence and achieved complete development within 4-15 d after emergence. The repeated observation of thoracic contents through the scutum showed very high sensitivity and specificity and apparently had minor effects on mortality. In another bug population located 360 km away, 16.4% of 177 males and 6.7% of 149 females had no flight muscles. Current results show that the sex-biased flight muscle dimorphism is a regionally widespread character in T. infestans. This character should be considered in field population studies that seek to measure reinfestation risk and dispersal in T. infestans and other Triatominae.