Study of the seasonal life cycle ofLutzomyia longiflocosa(Diptera: Psychodidae) under semi-controlled conditions in the department of Huila, Colombia

Abstract

AbstractBackground.Lutzomyia longiflocosais an insect vector associated with the transmission of Cutaneous Leishmaniasis. To establish the parameters of the life cycle ofL. longiflocosain semi-controlled conditions in a rural area of the Campoalegre municipality, Huila, Colombia.Methodology/Principal Findings.The life cycle of individuals ofLutzomyia longiflocosa, obtained from two cohorts of collected, fed, and individualized females, was monitored during two different times of the year (between February and August 2020 and between July 2020 and January 2021, respectively). Determining parameters associated with the fertility and fecundity, time and attributes of development and survival, and its association with abiotic variables. The average duration of Cycle 1 (C1) and Cycle 2 (C2) was 134.9 and 148.78 days, respectively. The gonotrophic cycle of parental females presented significant differences (p-value <0.05) between C1 and C2 (8.47 and 11.42 days) as well as between fecundity and fertility parameters. The number of days it takes the development of the immature stages between the two cycles studied, also showed significant differences in the larvae II (15.21 and 22.23), larvae III (11.93 and 17.56), and pupae (24.48 and 22.9) stages. During C1, the survival rate was higher and consistent with the productivity figures of adult individuals (F1), compared to C2. Fecundity and fertility values were significantly higher in C2. Finally, a significant correlation between the number of individuals and temperature was evidenced in C1 while, for C2, there was a negative correlation with precipitation.Conclusions/Significance.Significant differences were found in several biological and reproductive parameters between the two cycles monitored. The parameters of the life cycle ofL. longiflocosain its natural habitat would be influenced by environmental factors related to the annual seasonality in the sub-Andean rural area, conditioning the temporal distribution of this species and, consequently, the possible transmission of causative agents of cutaneous leishmaniasis.Author SummaryCutaneous leishmaniasis (CL) is a public health disease that affects more than 300 million people in tropical areas in the world and its causative agent is a parasite of the genusLeishmania. In recent decades, the cases in Latin America have increased, corresponding to 6% of cases in the tropical regions of the planet. An insect vector associated with the transmission of CL in these tropical and endemic areas isLutzomyia longiflocosa. Therefore, it is very important to investigate the environmental parameters that can influence its life cycle and its transmission capacity and competition, aspects that are not fully known.In Colombia, an endemic focus is located in the department of Huila, in a rural area of the municipality of Campoalegre, where this study was carried out. The authors found the relationship between some environmental parameters with the life cycle ofL. longiflocosaunder semi-controlled conditions in forested habitats, aspects that were not known until now. The impact of temperature, relative humidity, and precipitation on the gonotrophic cycle, fecundity, fertility, time of development and survival, was evidenced. This research provides information on the environmental conditions that directly affect the possible transmission of the agents that cause cutaneous leishmaniasis.