title: Copulation Activity, Sperm Production and Conidia Transfer in Aedes aegypti Males Contaminated by Metarhizium anisopliae: A Biological Control Prospect.
abstract: BACKGROUND
  Dengue is the most prevalent arboviral disease transmitted by Aedes aegypti worldwide, whose chemical control is difficult, expensive, and of inconsistent efficacy. Releases of Metarhizium anisopliae--exposed Ae. aegypti males to disseminate conidia among female mosquitoes by mating represents a promising biological control approach against this important vector. A better understanding of fungus virulence and impact on reproductive parameters of Ae. aegypti, is need before testing auto-dissemination strategies.
  
  
  RESULTS
  Mortality, mating competitiveness, sperm production, and the capacity to auto-disseminate the fungus to females up to the 5 th copulation, were compared between Aedes aegypti males exposed to 5.96 x 10(7) conidia per cm2 of M. anisopliae and uninfected males. Half (50%) of fungus-exposed males (FEMs) died within the first 4 days post-exposure (PE). FEMs required 34% more time to successively copulate with 5 females (165 ± 3 minutes) than uninfected males (109 ± 3 minutes). Additionally, fungus infection reduced the sperm production by 87% at 5 days PE. Some beneficial impacts were observed, FEMs were able to successfully compete with uninfected males in cages, inseminating an equivalent number of females (about 25%). Under semi-field conditions, the ability of FEMs to search for and inseminate females was also equivalent to uninfected males (both inseminating about 40% females); but for the remaining females that were not inseminated, evidence of tarsal contact (transfer of fluorescent dust) was significantly greater in FEMs compared to controls. The estimated conidia load of a female exposed on the 5th copulation was 5,200 mL(-1) which was sufficient to cause mortality.
  
  
  CONCLUSIONS
  Our study is the first to demonstrate auto-dissemination of M. anisopliae through transfer of fungus from males to female Ae. aegypti during mating under semi-field conditions. Our results suggest that auto-dissemination studies using releases of FEMs inside households could successfully infect wild Ae. aegypti females, providing another viable biological control tool for this important the dengue vector.
authors.affiliation: Laboratorio de Biomedicina Molecular, Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Tamaulipas, México.
authors.forename: Javier A
authors.initials: JA
authors.lastname: Garza-Hernández
authors.affiliation: Laboratorio de Biomedicina Molecular, Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Tamaulipas, México.
authors.forename: Filiberto
authors.initials: F
authors.lastname: Reyes-Villanueva
authors.affiliation: Faculty of Medicine, Health and Molecular Sciences, James Cook University, Cairns, Queensland, Australia.
authors.forename: Tanya L
authors.initials: TL
authors.lastname: Russell
authors.affiliation: National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
authors.forename: Marieta A H
authors.initials: MA
authors.lastname: Braks
authors.affiliation: Centro de Ciencias Agropecuarias, Universidad Autónoma de Aguascalientes, carretera a la Posta, Jesús María, Aguascalientes, México.
authors.forename: Alberto M
authors.initials: AM
authors.lastname: Garcia-Munguia
authors.affiliation: Laboratorio de Biomedicina Molecular, Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Tamaulipas, México.
authors.forename: Mario A
authors.initials: MA
authors.lastname: Rodríguez-Pérez
mesh_terms: D000330:Aedes / Q000382:microbiology* / Q000502:physiology*; D000818:Animals; D015169:Colony Count, Microbial; D003307:Copulation; D005260:Female; D008297:Male; D052981:Metarhizium / Q000302:isolation & purification*; D009032:Mosquito Control / Q000379:methods*; D010572:Pest Control, Biological / Q000379:methods*; D013091:Spermatogenesis; D013172:Spores, Fungal / Q000302:isolation & purification*; D016019:Survival Analysis