Aquatic Bugs Research Articles

Umbrella index as a conservation tool across pondscapes: A case study using frogs, aquatic insects, and plants in South Africa

Biological surrogates are valuable for conservation when they are easy and cost-effective to sample, sensitive to anthropogenic change, and show similar assemblage patterns to other taxa. The umbrella index (UI) developed by Fleishman et al. (2000), aims to conserve most species in an ecosystem by focusing on a single or small group of co-occurring species to represent all species present. Here we focus on various lentic aquatic insects (‘aquatic insects’ henceforth refers to aquatic beetles, aquatic bugs, and dragonfly larvae), adult dragonflies, frogs, and aquatic plants as potential surrogates for pond communities in the Midlands, KwaZulu-Natal Province, South Africa. There were some cross-taxon correlations, but these were too weak to consider for surrogacy, largely due to dissimilar responses to the same environmental gradients. However, using UI we identified five dragonfly species, nine aquatic insect species, and three frog species as potential umbrella groups for their own taxa. The UI for same-group surrogates was flexible and covered most taxa, ranging from co-occurring habitat generalists to rare specialist species. Furthermore, all four endemic species sampled here were effective surrogate species for other local taxa, with two of them ranking top in their own taxonomic group. The lack of congruence among the different taxa means that one taxon cannot be used to stand in for another. However, the UI allowed efficient site prioritization, so long as a multi-taxon approach is used. We recommend the UI approach when selecting surrogates to represent aquatic fauna within a pondscape of the Midlands of South Africa.

An investigation of the insect component in the diet of the Grey Heron Ardea cinerea and Little Egret Egretta garzetta

ABSTRACT Capsule Aquatic insects made up a relatively small part of the Grey Heron’s diet, while Little Egrets consumed numerous beetles, both aquatic and terrestrial. Aims To explore the extent of insect predation by Grey Herons and Little Egrets. Regurgitated pellets were collected from beneath trees in which herons and egrets were nesting. Methods Seventy Grey Heron and 48 Little Egret pellets were collected from the RSPB reserve at Northward Hill, Kent. These pellets were disaggregated and prey items were collected and sorted under a binocular microscope. Results Grey Herons fed on a relatively small number of aquatic beetles (Coleoptera: seven species, 32 individuals) and bugs (Hemiptera: two species, six individuals). Little Egrets, in contrast, fed on a diverse array of beetle species, both aquatic (three families, 11 species, 48 individuals) and terrestrial (10 families, 35 species, 111 individuals), and also a few aquatic bugs (one family, one species, three individuals). The extent of terrestrial beetles in the diet constitutes new information for Little Egrets. Conclusion Insects, both terrestrial and aquatic, represent an important component of the diet of Little Egrets. For Grey Herons, insects are a very minor component of the diet, involving aquatic species only.

Checklist of the aquatic and semiaquatic bugs (Hemiptera: Heteroptera: Gerromorpha, Leptopodomorpha & Nepomorpha) of Peru

The Peruvian fauna of aquatic and semiaquatic bugs comprises 233 species, representing 70 genera, 15 tribes, 29 subfamilies, and 16 families. Many of these species (22%) are endemic to the country, while 49% occur in Peru and other South American countries, 21% are found throughout the Neotropics, and 8% are widely distributed in the Americas. These proportions are similar among the three infraorders treated here. There is a slight predominance of Gerromorpha (48%) over Nepomorpha (46%) in Peru, and both are much more speciose than Leptopodomorpha (6%). The same Gerromorpha predominance also occurs in Colombia and Ecuador, whereas Nepomorpha is richer than Gerromorpha in Brazil, Argentina, and Chile. Within Peru, 92% of the species of aquatic and semiaquatic bugs have been recorded from the Atlantic slope, 16% occur in the Pacific slope, and only 2% in the Titicaca slope.

Description of a New Species and New Records of Naucoridae (Hemiptera: Heteroptera: Nepomorpha) from Eastern Brazil.

The aquatic bug family Naucoridae (Hemiptera: Heteroptera: Nepomorpha) is currently represented in Brazil by 68 species. Although the diversity of the family has been the target of several recent studies, large areas of the country are still unexplored and several species that have been deposited in entomological collections are waiting for a formal description. Aiming to fill these knowledge gaps, a series of expeditions were carried out in six states of eastern Brazil between 2018 and 2023: Alagoas, Bahia, Ceará, Espírito Santo, Pernambuco, and Sergipe. The fieldwork targeted protected areas, but surrounding regions were also explored. The material obtained, in addition to specimens previously deposited in a national entomological collection, revealed the existence of Australambrysus margaritifer Jordão, Santos and Moreira, a new species herein described, and new records for other 11 species and two subspecies belonging to the genera Carvalhoiella De Carlo, 1963, Limnocoris Stål, 1876, Maculambrysus Reynoso-Velasco and Sites 2021, and Pelocoris Stål, 1876.

Unveiling nature’s beat: analyzing the acoustics of an aquatic bug in relation to urban sounds

Anthropophony is a prominent component of soundscapes worldwide and is known to impact biota. While responses to anthropophony in terrestrial and marine animals have been relatively well-studied, there is still a lack of knowledge regarding freshwater animals. In fact, freshwater taxa are among the possibly most threatened groups, and unveiling the reasons for their threat is crucial. We investigated the effect of low-frequency sounds -usually associated with anthropophony- on the stridulation of Krizousacorixa femorata, a common water bug in Mexico City. Using aerial recordings, we estimated the Normalized Difference Soundscape Index (NDSI), which is the most commonly used index to measure anthropophony, to characterize soundscapes in six city sites throughout the year. Additionally, from underwater recordings in the same sites, we obtained the peak frequency (Pf) of the stridulations, as it is the frequency with the highest energy and, therefore, the one that can travel the farthest and can be identified even in the presence of overlapping sounds. Finally, we evaluated the relationships between soundscapes and Pf through a mixed linear model. There was a negative correlation between NDSI and Pf, indicating higher-pitched stridulations at sites with dominant anthropophony. While we cannot rule out other factors contributing to stridulation variation, we remain uncertain about how low-frequency sounds impact freshwater ecosystems and the intricate relationship between soundscapes and aquatic life in urban settings.

Study Of Aquatic Hemipteran And Coleopteran With Their Ecological Impacts: A Review

In the natural world, utilitarian diversification of the earthbound is predominantly composed of the amazing numerous and enormously sophisticated bugs and beetles. Investigation of biodiversity is one of the crucial ways of dealing with evaluating structure, overflow, and examination of occupying species in the different aquatic ecosystems. Aquatic bugs (water striders, water scorpions) and beetles (diving beetles, water scavenger beetles) are great signs of the organic soundness of an aquatic ecosystem since some of them are harmless and sensitive to contamination, while others can live in upset and incredibly dirtied waters. Hemiptera and Coleoptera are two significant orders that normally exist in oceanic frameworks, feeding on dead leaves or predaceous, interdependent for predation and competition, sometimes acting as a nuisance and structuring the foundation of aquatic habitats. Hence, there is need for a regular identification, habitat modification, monitoring, and conservation of these essential orders.

On an account of diversity of Aquatic and Semi Aquatic bugs from lower basin of Mundeswari river, West Bengal, India

The Mundeswari River, situated in West Bengal, serves as a tributary to the Damodar River. Its’ water plays a crucial role in both domestic and agricultural activities. However, during the monsoon season, the river poses a threat by causing floods in the Hooghly, Howrah, and East Medinipur districts. The Mundeswari River becomes a mixed blessing for the nearby villages. This study delves into the rich diversity of aquatic and semi-aquatic bugs in the lower basin of the Mundeswari River. The faunistic investigation reveals the presence of 14 species across 9 genera and 6 families, all of which are documented for the first time in this river.

A faunistic survey of the aquatic and semi-aquatic bugs (Hemiptera, Heteroptera) of the Tiger Reserves in Telangana, India

A faunistic survey of the aquatic and semi-aquatic bugs (Hemiptera, Heteroptera) of the Tiger Reserves in Telangana, India

Pelocoris Stl, 1876 of northeastern Brazil (Hemiptera: Heteroptera: Naucoridae): first records and a key to the species.

Naucoridae is a family of aquatic bugs, distributed in tropical and subtropical regions of the world, and comprises 437 species, 47 genera, and eight subfamilies. Five subfamilies, 10 genera and 68 species have been recorded from Brazil. Pelocoris Stl is a genus exclusive to the New World, with 14 species described; eight species and two subspecies have been recorded from Brazil. For the northeastern region, there are no records of occurrence for any species in this genus. The objective of this work was to survey the fauna of Pelocoris in the northeastern region and map the distribution of the species. We examined 180 specimens belonging to six species: Pelocoris binotulatus nigriculus Berg, 1879, P. bipunctulus (Herrich-Schffer, 1853), P. magister Montandon, 1898, P. poeyi (Gurin-Mneville, 1835), P. politus Montandon, 1897, and P. subflavus Montandon, 1898. This work contributes directly to reducing the Wallacean and Linnean gaps in Naucoridae diversity for northeastern Brazil and highlights the diversity in the region, which is still poorly studied and poorly known.

The first water treader (Heteroptera: Mesoveliidae) from the mid-Cretaceous Kachin amber

Myanmarvelia pankowskiorum gen. et sp. nov., is the first occurrence of the aquatic bug family Mesoveliidae in the mid-Cretaceous Kachin amber. This new taxon is described and illustrated based on a well-preserved female specimen. Although numerous morphological characters confirm its placement in the Mesoveliidae its position within the family is unclear. The presence of claws inserted pre-apically and head extended in front of eyes would suggest a placement in the Mesoveliinae but we consider it putative. The fossil record of this family is very poor, ranging between the late Jurassic and the Miocene.

DNA barcode-based survey documents underestimated diversity and intricate phylogeographic patterns of aquatic Heteroptera in an endangered Balkan biodiversity hotspot: ancient Lake Skadar basin

Lake Skadar with its surrounding springs, wetlands and larger affluents is among the most diverse freshwater ecosystems in the Mediterranean region and a key biodiversity/endemism hotspot in Europe. It is also highly endangered due to climate change and rapid tourism development in the area. Being abundant, diverse and mostly predatory, true aquatic bugs play an important role in the functioning of freshwater ecosystems and are used as indicators of aquatic habitat quality. Nevertheless, this taxonomic group has been scarcely studied in the area. Our survey provides the first comprehensive DNA barcode library for 24 out of 25 species of aquatic Heteroptera collected in the Skadar Lake basin and adjacent regions. By this, we extend the list of species known from the area by 60%. In the case of three species, Notonecta maculata, Hydrometra stagnorum and Nepa cinerea, we detected multiple highly divergent, and also new BINs indicating possible taxonomic inconsistencies, the potential for (pseudo)cryptic diversity and intricate phylogeographic patterns. We show that presumably well-known hotspots, such as Lake Skadar region, are heavily understudied regarding even the prominent insect taxa and, thus, particularly vulnerable to undocumented biodiversity loss. Finally, we underline the value of simple DNA-barcoding-based surveys for providing reference barcode libraries for effective biomonitoring and signalling taxonomic and biogeographic issues.

The oldest aquatic aphelocheirid bug (Heteroptera, Nepomorpha) from the lower Eocene of India

The aquatic bug family Aphelocheiridae currently comprises only the extant genus Aphelocheirus Westwood, 1833, with two subgenera, the nominal one and Micraphelocheirus Hoberlandt & Štys, 1979. The genus is widely distributed in Europe, Asia, Africa, but seems to be absent from the New World (Schuh & Weirauch, 2020). These small predatory insects live at the bottom of lakes and ponds, and breath thanks to highly specialized abdominal respiratory ‘rosettes’ characteristic of this family (Thorpe & Crisp, 1947a, b; Schuh & Slater, 1995). The closely related Naucoridae have to breathe at the surface of the water. Ye et al., 2020: fig. 4) proposed a late Triassic age for the Naucoroidea and separation between the Naucoridae and the Aphelocheiridae, but Wang et al. (2021: fig. 4) proposed that the (Potamocoridae + Aphelocheiridae) separated from the Naucoridae during the Jurassic and that the Aphelocheiridae could be early Cretaceous. The accurate aphelocheirid fossil record is very scarce, with the oldest known representative from the Eocene (Bartonian) of Germany (Moraweck et al., 2015); and a second fossil from the Pliocene of Germany (Popov, 2007; Kunzmann et al., 2017).

You are what you eat-ecological niche and microhabitat influence venom activity and composition in aquatic bugs.

True water bugs (Nepomorpha) are mostly predacious insects that live in aquatic habitats. They use their piercing-sucking mouthparts to inject venomous saliva that facilitates the capture and extra-oral digestion of prey animals, but their venom can also be deployed for defence. In Central Europe, nepomorph species representing different families coexist in the same habitat. However, their feeding ecology, including venom composition and deployment, has not been investigated in detail. We used an integrated proteotranscriptomic and bioactivity-based approach to test whether venom composition and activity differ between four water bug species sharing the same habitat but occupying different ecological niches. We found considerable species-dependent differences in the composition of digestive enzymes and venom components that probably evolved as adaptations to particular food sources, foraging strategies and/or microhabitats. The venom of Corixa punctata differed substantially from that of the three strictly predatory species (Ilyocoris cimicoides, Notonecta glauca and Nepa cinerea), and the abundance of herbivory-associated proteins confirms a mostly plant-based diet. Our findings reveal independent adaptations of the digestive and defensive enzyme repertoires accompanied by the evolution of distinct feeding strategies in aquatic bugs.

Effects of Different Types of Agricultural Land Use on the Occurrence of Common Aquatic Bugs (Nepomorpha, Heteroptera) in Habitats with Slow Flowing Water in Bulgaria, Southeast Europe

Agricultural activities can have a significant impact on aquatic organisms, including aquatic insects. Most of the aquatic Heteroptera are known as moderately tolerant to low oxygen and high nutrient concentrations. Nevertheless, the complex effects of agriculture (source of both pesticides and nutrient loads) on this group are still unclear. Therefore, the relationship between six agricultural land use classes and the occurrence of common aquatic bugs in Bulgaria was studied. In order to avoid detection bias, presence-only models were applied; Maxent algorithm was used. According to the results, land use practices connected to arable land (annual crops) have stronger influence on the occurrence of the selected aquatic Heteroptera species than those connected to perennial crops (vineyards and fruit trees). Higher sensitivity to the effects of agriculture was indicated for species preferring microhabitats without macrophyte vegetation, Aphelocheirus aestivalis (Fabricius, 1794) and Micronecta griseola Horváth, 1899, compared to species preferring macrophyte dominated sites, Nepa cinerea Linnaeus, 1758, Ilyocoris cimicoides (Linnaeus, 1758) and Sigara striata (Linnaeus, 1758).

Phylogeny and historical biogeography of the water boatmen (Insecta: Hemiptera: Heteroptera: Nepomorpha: Corixoidea)

The water boatmen of Corixoidea, a group of aquatic bugs with more than 600 extant species, is one of the largest superfamilies of Nepomorpha. Contrary to the other nepomorphan lineages, the Corixoidea are most diverse in the Laurasian remnant Holarctic region. To explicitly test whether the present-day Holarctic distribution of diverse corixids is associated with the arising of the Laurasian landmass that was separated from Gondwana, we investigated the phylogeny, divergence times and historical biogeography of Corixoidea based on morphological and molecular characters sampled from 122 taxa representing all families, subfamilies, tribes and approximately 54 % of the genera. Our results were largely congruent with the phylogenetic relationships within the established nepomorphan phylogenetic context. The fossil calibrated chronogram, diversification analysis and ancestral ranges reconstruction indicated that Corixoidea began to diversify in Gondwana in the late Triassic approximately at 224 Ma and the arising of the most diverse subfamily Corixinae in Corixidae in the Holarctic region was largely congruent with the time of separation of Laurasia from Gondwana. The large-scale expansion of the temperate and cold zones on the northward-moving Laurasian landmass after the breakup of the Pangea provided new aquatic niches and ecological opportunities for promoting rapid diversification for the Holarctic corixid lineage.

Differential abundance, composition and mesohabitat use by aquatic macroinvertebrate taxa in ponds with and without fish

Fish are known to pose strong effects on invertebrate abundance, species richness and assemblage structure. Littoral vegetation may play a crucial role as a refuge for invertebrates vulnerable to fish predation. We studied relative densities and taxonomic composition of water mites, aquatic beetles and bugs in large lake-like ponds with different fish status (fish-free and containing fish) and mesohabitats (emergent littoral vegetation and open water zone). The macroinvertebrate taxa differed in their responses to the fish presence and in mesohabitat preferences. The density and species richness of water mites were greater in fish-containing ponds, while no differences were found between littoral and open-water habitats. In contrast, beetles were far more numerous and species-rich in fish-free ponds and in littoral vegetation. Total densities of aquatic bugs were non-significantly higher in fish-containing ponds, and they preferred littoral areas, but species richness was independent of fish presence and mesohabitat. No statistical interactions between fish presence and the densities of individual macroinvertebrate groups in the littoral habitat were detected, indicating that their use of emergent littoral vegetation was not an antipredator response to fish. The assemblages of the three macroinvertebrate taxa exhibited nested structures of a different order, consistent with their species richness patterns. Our research stresses the importance of littoral vegetation for the distribution and abundance of aquatic insects; however, high fish presence may not affect or may even benefit ecologically important macroinvertebrate groups, such as water mites or bugs.

Symbiotic Microorganisms and Their Different Association Types in Aquatic and Semiaquatic Bugs.

True bugs (Hemiptera, suborder Heteroptera) constitute the largest suborder of nonholometabolous insects and occupy a wide range of habitats various from terrestrial to semiaquatic to aquatic niches. The transition and occupation of these diverse habitats impose various challenges to true bugs, including access to oxygen for the aquatic species and plant defense for the terrestrial phytophagans. Although numerous studies have demonstrated that microorganisms can provide multiple benefits to terrestrial host insects, a systematic study with comprehensive higher taxa sampling that represents aquatic and semiaquatic habitats is still lacking. To explore the role of symbiotic microorganisms in true bug adaptations, 204 samples belonging to all seven infraorders of Heteroptera were investigated, representing approximately 85% of its superfamilies and almost all known habitats. The symbiotic microbial communities of these insects were analyzed based on the full-length amplicons of the bacterial 16S rRNA gene and fungal ITS region. Bacterial communities varied among hosts inhabiting terrestrial, semiaquatic, and aquatic habitats, while fungal communities were more related to the geographical distribution of the hosts. Interestingly, co-occurrence networks showed that species inhabiting similar habitats shared symbiotic microorganism association types. Moreover, functional prediction analyses showed that the symbiotic bacterial community of aquatic species displayed richer amino acid and lipid metabolism pathways, while plant-feeding true bugs benefited more from the symbiont-provided xenobiotics biodegradation pathway. These results deepened the recognition that symbiotic microorganisms were likely to help heteropterans occupy diverse ecological habitats and provided a reference framework for further studies on how microorganisms affect host insects living in various habitats. IMPORTANCE Symbiotic bacteria and fungi generally colonize insects and provide various benefits for hosts. Although numerous studies have investigated symbionts in terrestrial plant-feeding insects, explorations of symbiotic bacterial and fungal communities in aquatic and semiaquatic insects are rare. In this study, the symbiotic microorganisms of 204 aquatic, semiaquatic, and terrestrial true bugs were explored. This comprehensive taxon sampling covers ~85% of the superfamilies of true bugs and most insect habitats. Analyses of the diversity of symbionts demonstrated that the symbiotic microbial diversities of true bugs were mainly affected by host habitats. Co-occurrence networks showed that true bugs inhabiting similar habitats shared symbiotic microbial association types. These correlations between symbionts and hosts together with the functions of bacterial communities indicated that symbiotic microbial communities may help true bugs adapt to (semi)aquatic habitats.

Species status of populations of Lethocerus indicus (Lepeletier and Serville, 1825) (Heteroptera: Belostomatidae) in Southeast Asia

The giant water bug, Lethocerus indicus (Lepeletier & Serville, 1825), is an aquatic true bug that has been included in the Vietnam Red Data Book since 1992 (“ca-cuong” in Vietnamese, “maeng-da” in Laos and Thailand). This insect also has been listed as an endangered species in Japan, Laos, and South Korea. This study aimed to (1) perform a genetic analysis to determine the species status of various populations of L. indicus in Southeast Asia, and (2) initially survey their distribution in Vietnam and Laos. Four populations were collected: two from the Vientiane Capital and Savannakhet Province areas of Laos, and two from the Vinh Phuc and Long An areas of Vietnam, respectively. Cytochrome oxidase subunit I (COI) fragments longer than 600 bps were amplified by polymerase chain reaction (PCR). Twelve nucleotide polymorphisms were found among these four populations. A maximum likelihood tree based on COI showed that the genetic distances among populations were very small, ranging from 0.2% to 1.1%, and were substantially distant from other populations of Lethocerus. Therefore, they are all considered to be conspecific and to represent L. indicus.

Diversity of the Heteroptera (Insecta: Hemiptera) aquatic and semi-aquatic assemblage of the Río Grande basin (Jujuy-Argentina) in an altitudinal and temporal gradient

The objective of this work was to realize a preliminary stydy the diversity, composition and structure of the aquatic and semiaquatic Heteroptera assemblage of Río Grande basin (Jujuy, Argentina) along a temporal and spatial gradient. For the first time, a list of the taxa inhabiting the area is presented, which includes 11 genera belonging to eight families. The sites corresponding to the lower basin exhibited higher diversity, and the genus Rhagovelia was the most abundant in both hydrological seasons. In contrast, the upper basin exhibited a low diversity, and its assemblage was dominated by Ectemnostega, both in the wet and dry season. Significant differences in the diversity of aquatic and semiaquatic bugs at the temporal level were not found in this basin.

The Adipokinetic Peptides of Hemiptera: Structure, Function, and Evolutionary Trends.

The Hemiptera comprise the most species-rich order of the hemimetabolous insects. Members of a number of superfamilies, most notably especially the more basal ones such as white flies, psyllids and aphids, belong to the most destructive agricultural insects known worldwide. At the other end of the phylogenetic tree are hemipterans that are notorious medical pests (e.g. kissing bugs). Most of the hemipteran species are good flyers, and lipid oxidation plays a pivotal role to power the contraction of flight muscles and, in aquatic water bugs, also deliver the ATP for the extensive swimming action of the leg muscles. Mobilization of stored lipids (mostly triacylglycerols in the fat body) to circulating diacylglycerols in the hemolymph is regulated by a set of small neuropeptides, the adipokinetic hormones (AKHs). We searched the literature and publicly available databases of transcriptomes and genomes to present here AKH sequences from 191 hemipteran species. Only few of these peptides were sequenced via Edman degradation or mass spectrometry, and even fewer were characterized with molecular biology methods; thus, the majority of the AKHs we have identified by bioinformatics are merely predicted sequences at this stage. Nonetheless, a total of 42 AKH primary sequences are assigned to Hemiptera. About 50% of these structures occur also in other insect orders, while the remaining 50% are currently unique for Hemiptera. We find 9 novel AKHs not shown to be synthesized before in any insect. Most of the hemipteran AKHs are octapeptides (28) but there is an impressive number of decapeptides (12) compared to other speciose orders such as Diptera and Lepidoptera. We attempt to construct a hypothetical molecular peptide evolution of hemipteran AKHs and find quite a bit of overlapping with current phylogenetic ideas of the Hemiptera. Lastly, we discuss the possibility to use the sequence of the aphid AKH as lead peptide for the research into a peptide mimetic fulfilling criteria of a green insecticide.