Maza Víctor A, Cardinal M Victoria, Nattero Julieta
Laboratorio de Eco-Epidemiología, DEGE (FCEN, UBA), IEGEBA (UBA/CONICET), Intendente Güiraldes 2160-Ciudad Universitaria - Pabellón 2, Ciudad Autónoma de Buenos Aires, CP: C1428EGA, Argentina.
Departamento de Ecología Genética y Evolución, Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.
Parasit Vectors. 2025 Mar 6;18(1):92. doi: 10.1186/s13071-025-06678-2.
Chagas disease, transmitted by triatomine bugs, is a major vector-borne parasitic disease in Latin America. Triatoma infestans, the principal vector in the Southern Cone, is primarily controlled through residual insecticide spraying. However, resistance to pyrethroids, especially in Northern Argentina and Southern Bolivia, has emerged. Resistant T. infestans populations exhibit reduced fitness, including impacts on reproductive success and dispersal capacity. This study investigates the flight potential and morphological changes in T. infestans populations with varying levels of insecticide resistance, hypothesizing that resistance may induce morphological changes in wing and head structures related to dispersal.
We analyzed three resistance profiles of T. infestans-susceptible (S), moderately resistant (MR), and highly resistant (HR)-collected from ten domestic or peridomestic sites in two municipalities from Chaco province, Argentina. We registered flight muscle development and measured flight-related traits (wings, heads, and the stiff and membranous portions of the wing) using a landmark-based methodology. We also assessed morphological disparity and covariation of these traits across toxicological groups.
Significant morphological differences were found between resistant and susceptible populations. The frequency of insects with and without muscle varied across toxicological groups only for females, exhibiting the highest proportion of HR insects with fight muscle (86.21%). MR and HR males exhibited smaller stiff portions of the wing and heads than S males. Shape variation analysis showed that S females had wider forewings than resistant females, while HR females had narrower wings with a wider stiff portion. Susceptible males had wider and longer wings compared with resistant groups. Additionally, resistant populations showed greater morphological disparity and reduced covariation between flight-related traits.
Our study shows that pyrethroid resistance in T. infestans is linked to morphological changes in flight-related traits. These changes suggest a tradeoff between resistance and flight capacity, with energy allocated to resistance mechanisms potentially limiting flight. The reduced covariation between flight traits in resistant individuals supports the idea of pleiotropic effects. While resistant individuals may perform better in insecticide treated areas, their reduced flight capacity could limit long-distance dispersal, affecting population dynamics and vector control efforts.
恰加斯病由锥蝽传播，是拉丁美洲一种主要的媒介传播寄生虫病。南锥体地区的主要传播媒介侵扰锥猎蝽主要通过残留杀虫剂喷洒进行控制。然而，对拟除虫菊酯的抗性已经出现，尤其是在阿根廷北部和玻利维亚南部。具有抗性的侵扰锥猎蝽种群适应性降低，包括对繁殖成功率和扩散能力的影响。本研究调查了不同杀虫剂抗性水平的侵扰锥猎蝽种群的飞行潜力和形态变化，假设抗性可能会导致与扩散相关的翅膀和头部结构发生形态变化。
我们分析了从阿根廷查科省两个市的10个家庭或家庭周边地点收集的侵扰锥猎蝽的三种抗性类型——敏感型（S）、中度抗性型（MR）和高度抗性型（HR）。我们记录了飞行肌肉的发育情况，并使用基于地标点的方法测量了与飞行相关的特征（翅膀、头部以及翅膀的硬部和膜部）。我们还评估了这些特征在不同毒理学组之间的形态差异和协变情况。
抗性种群和敏感种群之间存在显著的形态差异。仅雌性昆虫中，有飞行肌肉和无飞行肌肉的昆虫频率在不同毒理学组中有所不同，具有飞行肌肉的高度抗性型昆虫比例最高（86.21%）。中度抗性型和高度抗性型雄性的翅膀硬部和头部比敏感型雄性小。形状变异分析表明，敏感型雌性的前翅比抗性雌性宽，而高度抗性型雌性的翅膀较窄但硬部较宽。与抗性组相比，敏感型雄性的翅膀更宽更长。此外，抗性种群表现出更大的形态差异，且与飞行相关特征之间的协变减少。
我们的研究表明，侵扰锥猎蝽对拟除虫菊酯的抗性与飞行相关特征的形态变化有关。这些变化表明抗性和飞行能力之间存在权衡，分配给抗性机制的能量可能会限制飞行。抗性个体飞行特征之间协变的减少支持了多效性效应的观点。虽然抗性个体在经过杀虫剂处理的区域可能表现更好，但其飞行能力的降低可能会限制远距离扩散，从而影响种群动态和病媒控制工作。
