Effect of temperature and humidity on pathogenicity of native Beauveria bassiana isolate against Musca domestica L.

Abstract

Beauveria bassiana HQ917687 virulence to housefly larvae and adult was assessed at different relative humidity, RH (50, 75, 90, and 100 %) and temperature (15, 20, 25, 30, 35, 40, 45°C) conditions at the fungal dose of 10 8 conidia/ml. Depending on the temperature and RH regime tested, difference in mortality rates of housefly adult and larvae were detected. During assay on adult housefly, 100 % mortality was achieved at RH, 90 and 100 % while the temperature of 30°C showed maximum mortality at all the tested humidity conditions. Lethal time, LT 50 was 2.9 days at 100 % RH. Larval mortality at different humidity conditions varied between 30 and 74 %, with maximum mortality at 100 % RH and 30°C. Optimum temperature for B. bassiana virulence to housefly larvae was also found to be 30°C. The interaction between temperature and RH revealed significant effect of RH at moderate temperature range (20-35°C), while such an interaction was not observed at extreme temperatures. The results obtained in this study have useful implications in understanding the pathogen behavior under actual field conditions. This in turn may help devising suitable entomopathogen release schedules for maximum fungal infection.

Isolated individuals and groups show opposite preferences toward humidity

“…Low interest for high humidity levels by the groups might be related to a prophylactic strategy to reduce pathogen transmission. Indeed, higher humidity levels increase the speed of fungal development (Doberski, 1981;Mishra et al, 2015) should play an essential role in the aggregation process, as they are linked to the resistance to desiccation (Gibbs et al, 1997;Saïd et al, 2005), and constitute a first barrier against pathogen (Pedrini et al, 2013). Tackling quantitatively these bio-physico-chemical mechanisms and their relation to collective behaviour in social species would help to disentangle the distal causes of the inversion of the preferences between isolated individuals and individuals in groups observed in this study.…”

“…Low interest for high humidity levels by the groups might be related to a prophylactic strategy to reduce 76 pathogen transmission. Indeed, higher humidity levels increase the speed of fungal development [Doberski, 77 1981, Mishra et al, 2015 and the mortality rate [Hernandez-Ramirez et al, 2008] while it has been suggested that 78 low humidity levels reduce horizontal transmissions of pathogens [Quesada-Moraga et al., 2004]. Furthermore, 79 the composition of the cuticular hydrocarbons should play an essential role in the aggregation process, as they 80 are linked to the resistance to desiccation [Gibbs et al, 1997, Saïd et al, 2005, and constitute a first barrier 81 against pathogen [Pedrini et al, 2013].…”

Distribución potencial de Musca domestica en el municipio de Jesús María, Aguascalientes, con el uso de escenarios de cambio climático

“…de Larvas Tratamientos sobrevivió de larva a pupa (12 pupas de 122 larvas); esto se pudo deber a la alta HR que fue del 90 % a las que fueron expuestas; mismo efecto fue observado en un estudio en donde la máxima mortalidad se presentó al llegar al 100 % de HR y una temperatura superior a los 30 °C (22) . La pupa tolera menor humedad que la larva y puede desarrollarse a temperatura de 35 a 40 °C pero solo en un periodo mínimo de 3 a 4 días (18) , mientras que en este estudio, las pupas permanecieron por 16 días y a temperaturas 35 °C.…”

“…Al realizar el análisis de la transformación de pupa a adulto, el tratamiento 2 y 1 porcentualmente son mejores con el 84 y 74 % respectivamente de emergencia (54 y 85 adultos respectivamente). En el caso del T2 con una HR de 62.5 ± 2.5 % se acerca a lo reportado en estudios similares, donde mencionan que la HR óptima para el desarrollo de la mosca es de 65 a 75 % (22) . Es por eso que este tratamiento es más consistente en cuanto al desarrollo de sus diferentes etapas.…”

“…RCP45, desarrollado por la UNAM. Los resultados de este experimento muestran que la temperatura es el valor más significativo que induce la mortalidad (22) de M. domestica, mientras que la humedad relativa jugó un papel importante en la regulación de la viabilidad, pero a un rango moderado de temperatura.…”