The role of a water bug,Sigara striata, in freshwater food webs

Abstract

Freshwater food webs are dominated by aquatic invertebrates whose trophic relationships are often poorly known. Here, I used laboratory experiments to study the role of a water bug, Sigara striata, as a potential predator and prey in food webs of stagnant waters. Multiple-choice predation experiment revealed that Sigara, which had been considered mostly herbivorous, also consumed larvae of Chironomus midges. Because they often occur in high densities and are among the most ubiquitous aquatic insects, Sigara water bugs may be important predators in fresh waters. A second experiment tested the role of Sigara as a potential prey for 13 common invertebrate predators. Mortality of Sigara inflicted by different predators varied widely, especially depending on body mass, foraging mode (ambush/searching) and feeding mode (chewing/suctorial) of the predators. Sigara was highly vulnerable to ambush predators, while searching predators caused on average 8.1 times lower mortality of Sigara. Additionally, suctorial predators consumed on average 6.6 times more Sigara individuals than chewing predators, which supports previous results hinting on potentially different predation pressures of these two types of predators on prey populations. The importance of these two foraging-related traits demonstrates the need to move from body mass based to multiple trait based descriptions of food web structure. Overall, the results suggests that detailed experimental studies of common but insufficiently known species can significantly enhance our understanding of food web structure.

From water striders to water bugs: the molecular diversity of aquatic Heteroptera (Gerromorpha, Nepomorpha) of Germany based on DNA barcodes

“…With the exception of the omnivorous Corixidae, all aquatic true bugs are predators, feeding on any organism that can be subdued by the injection of a venom cocktail consisting of various toxins and proteolytic enzymes ( Polhemus & Polhemus, 2008 ). On the other hand they serve as important prey for numerous fish and other organisms at higher trophic levels ( McCafferty, 1981 ; Peckarsky, 1982 ; Zimmermann & Spence, 1989 ; Hutchinson, 1993 ; Klecka, 2014 ; Boda et al, 2015 ).…”

Bipartite graphs in systems biology and medicine: a survey of methods and applications

“…Ecological networks can be further subdivided into 3broad types: food webs (FWs), mutualistic webs (MWs), and host–parasitoid webs (HPWs). Although all 3 types contain trophic interactions, studies of FWs, according to the most strict definition, typically focus on predator–prey interactions where consumers that are usually bigger than their resources are involved [77].…”

“…The availability of quantified webs highlighted the importance of link strength, establishing the notion that the strength of the interaction plays an important role in stability, with many weak and few strong links leading to stable but potentially complex webs. More recently, the focus has shifted again from exploring the magnitude of complexity and the strength of interactions to approaches for understanding the specific configuration of complexity (e.g., clustering, the importance of loops or motifs, and so on) [77]. All of the above are also verified by the analysis of the trends in establishing new metrics and algorithms suitable for quantitative networks, as well as the development of new methods for community detection or evaluation of the dynamic properties of the system (see below) [91].…”

Anthropogenic stressors are driving a steep decline of hemipteran diversity in dune ponds in north-eastern Algeria

“…Two clear community structures, dominated by notonectids and corixids, respectively, emerged from the multivariate analysis. Although the detailed trophic posi-tion of most corixids and notonectids is poorly known (Klecka 2014), their differential distribution across the study ponds and hydrological cycles suggest distinct responses to anthropogenic pressures that may shed some light on the food web structures of dune ponds.…”