Spatial and temporal distribution of gerrid (Heteroptera) and predation on microcrustaceans from a tropical shallow lake

Abstract

Predator-prey interactions involving an aquatic insect and zooplanktonic prey of different sizes were investigated to quantify prey mortality exposed to predators. Laboratory experiments were undertaken with the young and adult gerrid Rheumatobates crassifemur to test predation and size selectivity on the cladocerans Daphnia gessneri, Ceriodaphnia richardi, and Bosmina tubicen. Population fluctuations and spatial distribution of the gerrid were also evaluated in a small and shallow Brazilian lake throughout 12 months in fortnightly samples. The insects were more abundant in the littoral (mean density 7.0 ± 1.2 ind.m -2 ) compared to the limnetic zone. The period with the highest densities was late January to June, in both zones. Predation by young instars on Daphnia and Ceriodaphnia was significant (mean ingestion rate of 1.3 ± 0.1 D. gessneri and 0.7 ± 0.1 C. richardi per predator per hour). Adult insect fed only the large-sized prey (mean ingestion rate of 1.0 ± 0.1 D. gessneri per predator per hour). Young gerrids have greater potential to prey on cladocerans than adults, and size selectivity occurred for both predators. Preference of adults by the larger prey is probably related to difficulties in manipulating smaller planktonic prey, such as Ceriodaphnia. Due to higher densities of insects in the littoral, higher predation on zooplankton in this zone is expected. This study does contribute to a better understanding of trophic interactions in tropical shallow lakes and is the first to investigate predation of a gerrid on cladocerans in laboratory experiments.Keywords: predation, gerrids, aquatic insects, zooplankton, neotropical lake.Distribuição espacial e temporal de gerrídeo (Heteroptera) e a predação sobre microcrustáceos de um lago tropical raso ResumoForam investigadas as interações predador-presa, envolvendo inseto aquático e presas zooplanctônicas de diferentes tamanhos para quantificar a mortalidade das presas expostas a predadores. Experimentos de laboratório foram realizados com jovens e adultos do gerrídeo Rheumatobates crassifemur para testar a predação e a seletividade por tamanho das espécies de cladóceros Daphnia gessneri, Ceriodaphnia richardi e Bosmina tubicen. Flutuações populacionais e a distribuição espacial do gerrídeo também foram avaliadas em um lago brasileiro pequeno e raso durante 12 meses em amostras quinzenais. Os insetos foram mais abundantes no litoral (densidade média 7,0 ± 1,2 ind.m -2 ) em comparação com a zona limnética. Maiores densidades ocorreram de fim de janeiro a junho, em ambas as zonas. A predação dos jovens foi significativa sobre Daphnia e Ceriodaphnia (taxa de ingestão média 1,3 ± 0,1 D. gessneri and 0,7 ± 0,1 C. richardi por predador por hora). Adultos predaram somente a presa maior (taxa de ingestão média 1,0 ± 0,1 D. gessneri por predador por hora). Gerrídeos jovens têm um maior potencial para predar cladóceros que os adultos, e seletividade por tamanho ocorreu para ambos. A preferência dos adultos somente pela presa maior provavelmente está relacionad...

Experiments on invertebrate predation on cladocerans and its relationships with lake data

“…Gerrids are also more abundant in the littoral zone, although at lower densities (~ 7 ind m -2 ) than notonectids (Domingos and Arcifa, 2017b). The cladocerans C. richardi and D. gessneri were preyed on by gerrids in experiments, with gerrid juveniles preying on both species and adults preying only on Daphnia (Domingos and Arcifa, 2017b). DNA extracted from the digestive tube of notonectids and gerrids from the lake revealed the ingestion of cladocerans, such as Daphnia and Diaphanosoma (AR Domingos et al, in preparation).…”

“…Notonectids occur in higher densities in the littoral zone (~ 140 ind m -2 ) than in the limnetic zone, and their juveniles preyed on Ceriodaphnia richardi and Daphnia gessneri in laboratory experiments (Domingos and Arcifa, 2017a). Gerrids are also more abundant in the littoral zone, although at lower densities (~ 7 ind m -2 ) than notonectids (Domingos and Arcifa, 2017b). The cladocerans C. richardi and D. gessneri were preyed on by gerrids in experiments, with gerrid juveniles preying on both species and adults preying only on Daphnia (Domingos and Arcifa, 2017b).…”

Distribución Espacio - Temporal De Insectos Acuáticos en Quebradas De La Llanura Amazónica, Loreto, Perú.

“…Estudios sobre la distribución espacio-temporal de insectos acuáticos han sido realizados con la finalidad de conocer su relación con las condiciones del ambiente (Marshall et al, 2006;Heino & Mykra, 2008;Burgazzi et al, 2018;Mendes et al, 2018;Bacca et al, 2021); determinar su preferencia de hábitats (Henriques-Oliveira & Nessimian, 2010b;Fontanarrosa et al, 2013;Serna et al, 2015;Souza et al, 2015), y rol trófico (Butakka et al, 2014;Domingos & Arcifa, 2017). Estas informaciones, sumada al destacado papel bioindicador que tienen estos organismos, pueden ser de gran utilidad para implementar programas de biomonitoreo de la calidad del agua en un área determinada.…”