Ecological relationships of Haemagogus spegazzinii (Diptera: Culicidae) in a semiarid area of Brazil

Abstract INTRODUCTION: Haemagogus are mosquitoes with diurnal habits that live preferentially in forest areas. In Brazil, they are considered the primary vectors of wild yellow fever. METHODS: The ecological relationships between Haemagogus spegazzinii, the environment, and some of its activities in the semiarid region of Rio Grande do Norte were analyzed by collecting eggs with ovitraps, actively searching in tree holes, capturing adults in Shannon traps, and conducting an investigation for viral infections. RESULTS: A total of 2420 eggs, 271 immature specimens (larvae and pupae), and 206 adults were collected. Egg collection depended on rainfall and relative humidity, with oviposition occurring between January and May. Larvae were found in five plant species, including Tabebuia aurea (craibeira), with 160 larvae collected. We observed shared breeding sites between Hg. spegazzinii and the following species: Aedes albopictus, Aedes terrens, Culex spp., and Toxorhynchites theobaldi. Adults exhibited greater activity between 5 pm and 6 pm, when 191 (92.7%) specimens were captured, while only 1 (0.5%) was collected between 7 pm and 8 pm. The relationship between Hg. spegazzinii and rainfall was significant, with positive correlations with accumulated rainfall 5, 10, 15, 20, and 30 days before mosquito collection. We found that the species was infected with the DENV-2 virus. CONCLUSIONS: This work contributes new information on the bioecology of Hg. spegazzinii, with data on the main reproduction periods, oviposition, breeding sites, activity times, and the relationship between the species and meteorological variables in the Caatinga of northeastern Brazil.

摘要 引言：趋雪蚊属（Haemagogus）为昼行性蚊类，偏好栖息于林区。在巴西，该属蚊类被认定为野生型黄热病的主要传播媒介。
方法：本研究通过诱卵器采集卵样、主动探查树洞、使用香农诱捕器（Shannon traps）捕获成蚊，并开展病毒感染检测，分析了斯佩加齐尼趋雪蚊（Haemagogus spegazzinii）、其生存环境与该蚊在北里奥格兰德州半干旱地区的部分活动之间的生态关系。
结果：本次研究共采集到2420枚卵、271份未成熟标本（幼虫与蛹）以及206只成蚊。卵的采集量与降雨量及相对湿度密切相关，产卵活动集中于1月至5月期间。幼虫共发现于5种植物的积水生境中，其中包括黄钟木（Tabebuia aurea，俗称craibeira），共采集到160只幼虫。本研究观察到斯佩加齐尼趋雪蚊与以下蚊种共享滋生地：白纹伊蚊（Aedes albopictus）、特伦斯伊蚊（Aedes terrens）、库蚊属（Culex spp.）以及西奥博尔德巨蚊（Toxorhynchites theobaldi）。成蚊的活动高峰集中于下午5时至6时，此间共捕获191只个体，占总捕获量的92.7%；仅在晚7时至8时捕获1只个体，占比0.5%。斯佩加齐尼趋雪蚊的种群数量与降雨量呈显著正相关，与蚊类采集前5、10、15、20及30天的累积降雨量均呈正相关关系。本研究还检测到该蚊种感染了登革病毒2型（DENV-2）。
结论：本研究为斯佩加齐尼趋雪蚊的生物生态学特征提供了全新数据，涵盖了该蚊种在巴西东北部卡廷加（Caatinga）旱生林区的主要繁殖周期、产卵行为、滋生地、活动时段，以及其与气象变量之间的关联。