Bamboo, clay and plastic artisanal ovitraps for mosquito surveillance across an urban–forest gradient in Colombia, with a video record of maternal care in Trichoprosopon digitatum

Abstract Low-cost ovitraps are the backbone of Aedes surveillance in cities, but their value for monitoring the wider mosquito community, including sylvatic species, is poorly known. We evaluated artisanal ovitraps (“OviCol”) made of plastic, fired clay and bamboo ( Guadua sp), baited with canary seed ( Phalaris canariensis ) or sugarcane molasses with dry yeast ( Saccharomyces cerevisiae ), in three phases in Santa Marta, northern Colombia. In Phase 1, six plastic ovitraps placed in tropical humid forest in the foothills of the Sierra Nevada de Santa Marta (SNSM) collected 20 eggs and 63 larvae of Trichoprosopon digitatum and 19 larvae of Limatus durhamii . They also yielded what is, to our knowledge, the first video record of egg brooding in this species: a female guarded her egg raft for at least 7 h and resumed brooding after the raft was removed and returned. In Phase 2, 83 ovitraps on an urban university campus collected 43,764 Aedes eggs in 28 days. Positivity did not differ among materials, but plastic and bamboo traps accumulated about three times more eggs than clay traps (rate ratios 3.09 and 3.61), whereas the attractant had no detectable effect. Egg counts showed field evidence of skip oviposition, and 19 persistent traps held 62% of all eggs. An artificial-intelligence counter (Col-Ovo) agreed with manual counts (CCC = 0.79, rising to 0.95). Larvae reared from positive traps included Ae. aegypti, Culex quinquefasciatus, Cx. (Carrollia) cf. bihaicola, Cx. (Phenacomyia) corniger and Ae. albopictus , the first evidence of this invasive vector in Santa Marta. In Phase 3, ovitraps in the SNSM forest yielded a Sabethini-dominated assemblage ( Tr. digitatum, Li. durhamii, Wyeomyia spp.) together with Orthopodomyia cf. fascipes, Toxorhynchites (Lynchiella) sp. and Cx. nigripalpus, with no Aedes detected. Simple, inexpensive traps therefore detected invasive urban vectors, sylvatic potential vectors and natural predators, and documented a rarely observed behavior. Clay traps are adequate for presence–absence surveillance, plastic or bamboo traps are preferable when egg density or egg removal is the goal, and clay and bamboo offer biodegradable alternatives to plastic.