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Jaiswal D, Banerjee S. 2024. Notes on Gerridae (Hemiptera: Heteroptera: Gerromorpha) from the Eastern Ghats of Telangana and Northern Andhra Pradesh, India. Nusantara Bioscience 16: 43-53. Gerridae is the family of semi-aquatic bugs found in both the lentic and lotic freshwater bodies. The present study focused on the Gerridae from the Eastern Ghats of Telangana and Northern Andhra Pradesh, India. This study documented a total number of 16 species belonging to 13 genera and 7 subfamilies under the family Gerridae. Tenagogonus nicobarensis Andersen, 1964, was earlier described from Andaman and Nicober islands and also known to be endemic to that particular geographical area. We are recording this species for the first time from the mainland of the Indian subcontinent. Ventidius aquarius Distant, 1910 was also recorded for the first time during this present study from the Eastern Ghats, an endemic species to peninsular India. Another species, Naboandelus signatus Distant, 1910 is also recorded from the Eastern Ghats of Andhra Pradesh as well as an addition to the state fauna of Andhra Pradesh. It is a widespread species and reported from both central and northeastern India. In southern India, it was reported from the two states and present record will be the additional third state to its distribution. In addition to taxonomic details, the article covers the geographic distribution of the 16 species. This study has also led to the addition of nine species of Gerridae to the state fauna of Andhra Pradesh. [ABSTRACT FROM AUTHOR]

This paper presents the inventory of exclusively marine Heteroptera species, including taxa of three families of Gerromorpha, Hermatobatidae, Veliidae, and Gerridae, from Vietnam. A new species of coral treaders, Hermatobates sanho sp. nov. from the southern area of Vietnam is described. Xenobates murphyi Andersen, 2000 and Xenobates singaporensis Andersen, 2000 are recorded from the country for the fi rst time. [ABSTRACT FROM AUTHOR]

Telmatometra withei (Bergroth, 1908) is a common water strider found across the Neotropics. Although, the taxonomy of T. withei is relatively well known, the specie's life cycle has not been characterized. We use field surveys and laboratory experiments to describe the life cycle of two populations of T. withei in the Pacific coast of Panama. Specifically, we compared the life cycle between fresh and brackish water populations known to show local adaptation to each environment. We also contrast the life cycle of T. withei with that of other water striders previously reported in the literature. We found that the average life cycle of T. withei is approximately 66.7 days, and this period did not vary significantly between fresh (65.0 days) and brackish (68.3 days) populations. However, these estimates were longer than those reported for other species of water strides. In addition, traits associated with reproductive success such as egg length and fecundity varied significantly between populations, with females from freshwater populations showing larger values. This suggests that salinity can have important consequences for reproductive traits in T. withei, even if the overall life cycle may not be affected by salinity. Thus, characterizing the life history of these Neotropical organisms is crucial to understand the rich freshwater biodiversity of this region, as well as its response to both natural and anthropogenic disturbances. [ABSTRACT FROM AUTHOR]

Water strider (Gerridae) morphology and behavior have become the focus of interdisciplinary research in biological diversification and bio-inspired technology. However, the diversity of behaviors and morphology of the large-sized Gerridae have not been intensely studied. Here, we provide locomotory behaviors and legs' micro-morphology of the large South-East Asian water strider, Ptilomera tigrina. Using high-speed videography and experiments in natural habitats, as well as scanning electron microscopy of midlegs, we have determined that (1) P. tigrina individuals prefer relatively high flow speeds of 0.15–0.30 m/s, compared to other water striders previously studied, and they are also observed in very high flow speeds of up to 0.6 m/s; (2) they avoid stagnant water, but when on still and very slow flowing water they perform constant back-and-forth rowing using their midlegs; (3) their antipredatory reaction involves repetitive and very fast "protean" movements propelled by the midlegs; (4) their midleg tarsi and tibiae are equipped with brushes of ribbon-like hairs, which are used as paddles for rowing. As the locomotory behaviors and flow-speed preferences by P. tigrina require constant use of midlegs for rowing, the presence of special paddle structures on midlegs illustrates a hypothetical adaptive match between midlegs' locomotory function and their micro-morphology. [ABSTRACT FROM AUTHOR]

The objective of this study was to describe the structure and histochemistry of the systemic organs in the female marine water-strider Asclepios annandalei from Pranburi river estuary, Thailand. Results from this study revealed for the first time that the integumentary system of this species consisted of three layers including epicuticle, exocuticle and endocuticle. The muscular system apparently contained only skeletal muscle along the body. In the urinary system, we observed well-developed Malpighian tubules, each of which was covered with the simple cuboidal epitheliums. These epitheliums also contained the secretory granules that were reacted positively with periodic acid Schiff (PAS). The digestive system of this species was composed of three distinct parts including foregut, midgut and hindgut. The respiratory system was composed of the respiratory organ, which was rarely found near the integument system. This organ was lined with a simple squamous epithelium. Two regions of nervous system, i.e., frontal ganglion connected to the eye structure and ventral nerve cord, were found. Each ganglion basically consisted of two layers, outer cortex and inner medullae. The outer cortex contained three types of cells, including neurosecretory cells, neuroglial cells and neurons. The cytoplasmic inclusion of neurosecretory cells contained secretory granules, which reacted positively with PAS, indicating the presence the glycoprotein. The neuroglia and neuron were also observed in the inner medullae layer. The female reproductive system (the ovarian structure, the reproductive tract and the accessory organ) of this gerrid species was seen under histological sections. The well-developed integument system and Malpighian tubule as well as the abundant respiratory organ is a characteristic of this species, which might be useful for the adaption to the estuarine condition. [ABSTRACT FROM AUTHOR]

The type specimens of the water strider family Gerridae housed in the Natural History Museum Vienna are catalogued. Information on type status, label data, and current taxonomic status is provided. The treated material consists of 1242 specimens of 153 nominal taxa of species and subspecies, including 47 holotypes, 4 lectotypes, 50 syntypes (including 2 questionable), 14 paralectotypes, and 1127 paratypes (including 11 allotypes). Photographs of 88 type specimens are provided. [ABSTRACT FROM AUTHOR]

This study aims to illustrate distribution of semiaquatic bug species in Guadeloupe (Lesser Antilles), as there is still little knowledge about the biodiversity of the island's mangroves. In addition to Limnogonus franciscanus Stål, 1859 and Rheumatobates imitator Uhler, 1894, four species are newly reported for Guadeloupe: Brachymetra albinerva Amyot and Servilles, 1843, Rhagovelia plumbea Uhler, 1894, Rheumatobates mangrovensis China, 2009 and R. trinitatis China, 2009 based on taxonomic and phylogenetic analyses. For all recorded species, we provide detailed data on their ecology and distribution in the region of the investigation. [ABSTRACT FROM AUTHOR]

El presente trabajo resume las principales tendencias en el conocimiento de los gerromorfos en el ámbito mundial, relacionadas con los avances en sistemática molecular, su uso como indicadores de ambientes cambiantes y la ampliación del saber en varios países Neotropicales. Se revisa la información publicada sobre los Gerromorpha en la última década (2009-2019) en Colombia y se contemplan los diferentes aspectos biológicos, taxonómicos, ecológicos y de distribución geográfica. El desarrollo y el progreso sobre los heterópteros semiacuáticos son la base del emprendimiento de otras investigaciones en Colombia y en el Neotrópico, especialmente en regiones como Mesoamérica y Sudamérica.

Among millions of insect species known in the world only five species of Halobates (Heteroptera: Gerridae) are able to live in the high seas. The general public is probably not aware that there are insects living on the open ocean and even most marine scientists have never seen a live or preserved specimen with their own eyes. The genus Halobates was first collected during a Russian oceanographic expedition around the world between 1815 and 1818.

The present work summarizes the main worldwide trends in the Gerromorphans knowledge which are related to the advances in molecular systematics, their use as indicators of changing environments, and knowledge broadening in several Neotropical countries. The information published about Gerromorphans in last decade (2009-2019) in Colombia is reviewed, and the different biological, taxonomic, ecological and geographical distribution aspects are considered. The development and progress about semiaquatic Heteroptera are the base to undertake further investigations in Colombia and at the Neotropic, especially in regions such as Mesoamerica and South America. [ABSTRACT FROM AUTHOR]

Aim: Local environmental selection and lineage admixture have long been accepted as important adaptive mechanisms in adjusting widespread taxa to new environments. We studied a pond skater, Gerris latiabdominis, to explore the relative roles played by these two mechanisms in its process of adaptation to heterogeneous landscapes. Location: East Asia. Taxon: Gerris latiabdominis Miyamoto, 1958. Methods: Mitochondrial (COI, COII) and nuclear (ddRAD‐seq) markers were sequenced from 202 individuals. Phylogenetic and phylogeographical analyses were conducted to reveal the population genetic structure. The demographical history was simulated by approximate Bayesian computation (ABC). The single‐nucleotide polymorphisms (SNPs) that may have been subjected to natural divergent selection among the populations were assessed, and the recent migration rates were estimated. Finally, shifts in suitable habitat from the last interglacial (LIG) to the present were predicted through ecological niche modelling (ENM). Results: We found population structures inferred from both mitochondrial and nuclear genomes to be almost coincident and to correspond to temporal or spatial heterogeneity. The early Pliocene splitting event between the northern (NO) and southeastern (SE) groups is consistent with the 'arid belt hypothesis', followed by local environmental selection. Approximate Bayesian computation and gene flow estimation strongly suggested that the southwestern (SW) groups originated from a lineage admixture event between the SE and western (WE) groups and subsequently underwent ongoing gene flow from the SE group during the Pleistocene. The mito‐nuclear discordance pattern in the SW group was probably due to the ancient mitochondrial differentiation. Main conclusion: Our results suggest that both local environmental selection and lineage admixture acted as significant mechanisms of G. latiabdominis adaptation to heterogeneous landscapes in East Asia. Furthermore, this study showed that conclusions based exclusively on mitochondrial data might mislead taxonomic, phylogenetic and phylogeographical studies. [ABSTRACT FROM AUTHOR]

We investigated the phylogenetic relationships among seven of the ten Halobatinae genera (Heteroptera: Gerridae) based on COI+II, 16S rRNA, and 28S rRNA genes. Our analyses recovered monophyly of Halobatinae, and suggested paraphyly of Metrocorini caused by the position of Ventidius and Esakia. Since our phylogenies did not infer monophyly of the subgenus Halobates (s.str.) within Halobatini, we synonymized Austrobates and Halobates (Hilliella) with Halobates. We confirmed that (1) the limnic lifestyle of Metrocorini was ancestral in Halobatinae, (2) the marine lifestyle evolved only once in the common ancestor of Asclepios + Halobates , (3) the limnic lifestyle of some members of Halobates was independently derived from marine ancestors, and that (4) the open ocean was colonized at least three times in Halobates. A catalogue of Halobatinae organized according to an updated classification is presented, including all known geographic distributions, bibliographical references, and additional notes to all species of the subfamily. [ABSTRACT FROM AUTHOR]

Two species of ocean skaters, Halobates germanus and Halobates micans, live in the tropical and subtropicalwaters of the Indian Ocean. From December 1992 to December 1993, Halobates was intensively sampledin the easternmost region of the South Indian Ocean (13–18.5°S, 114–121E°), from which there have been a small number of records of Halobates. No H. germanus was caught, but a total of 1190 H. micans were collected, with densities estimated at 13 900–28 100 individuals/km2. This suggests that H. micans lives in the study area at high densities comparable to those in the Atlantic and the Pacific Oceans. We also discuss the possible effects of ocean currents and winds on the geographic distributions of the two Halobates speciesin the eastern South Indian Ocean.

While water striders (Hemiptera: Gerridae) have a global distribution different species have adapted to very different habitat types. Freshwater water striders such as Limnogonus luctuosus live in areas along streams and rivers with little to no flow. Marine water striders, such as coastal species Halobates hawaiiensis, have adapted to life on the surface of the ocean. Since these types of water striders live in such different habitats, and face different environmental factors their food preference and behavior can be quite different. In this study, average density of L. luctuosus individuals was measured along the Opunohu River. Also, food preference, behavior, and the effects of increased density were tested in the laboratory for both L. luctuosus and H. hawaiiensis. Response time and frequency of approach to mobile and immobile prey items were recorded for H. hawaiiensis and L. luctuosus. H. hawaiiensis preferred immobile prey while L. luctuosus preferred mobile prey. Frequency of several behaviors (i.e. movements, moving away from others, approached by others, approaching others, attacking, being attacked, jumping, and cleaning) were compared between species, and within species at increasing densities. There were differences between species in the frequency of movements, approaching others, being approached, jumping, and cleaning. Density affected movements, moving away from others, jumping, and cleaning for H. hawaiiensis. Density affected movements, moving away from others, and cleaning behaviors for L. luctuosus. The different ecology of these two species can be used to explain why differences exist in both food preference and frequencyof behaviors.

Among the million or so insect species known, only a few thousand are found in marine habitats. The genus Halobatesis almost exclusively marine and is unique in having the only known species to live in the open ocean. Of the 46 Halobatesspecies described, only five are completelyoceanic in habitat, with the majority of species living in coastal areas associated with mangroves or other marine plants. This review presents a brief historical account of the genus and providesinformation on various aspects of its life history, ecology, special adaptations, distribution, and biogeography. Distribution maps of the five oceanic species as well as several of the more widely distributed coastal species have been updated. The phylogeny and evolution of Halobatesbased on morphology and recent molecular data are also discussed. A key to all known species of Halobatesand related genera and a checklist of all species and their distributions are included as appendices.

Specimens of ocean skaters Halobates were collected off the south coast of Japan in the East China Sea in 1995, and from the Kumano-nada Sea to the East China Sea in 1998 and 1999. Three species were identified: H. micans, H. germanus and H. sericeus.  We found two species co-occurring in comparable densities in different years, a phenomenon not hitherto reported in other regions of the ocean. We discuss distributions of the three Halobates species with special reference to the influence of the Kuroshio Current, temporal variations of sea-surface temperature, and monsoonal winds.

A list of marine Heteroptera and Diptera currently known from Guam is given. Some notes on biology and distribution are alsoincluded.

Semiaquatic bugs (Hemiptera: Heteroptera: Gerromorpha) are mostly wing-polymorphic species with flight dispersal as an important life history trait, but the specific flight ability and dispersal pattern remain unexplored in most species. This report presents the results of a long-term survey based on the individual marking of more than 23,000 specimens of eight water striders (Gerridae) and a water cricket Velia caprai (Veliidae). Three distinct lentic habitats were sampled (solitary fishponds, systems of nearby fishponds and systems of small, often temporary pools) and one lotic habitat—a small forest stream. Recaptures revealed that three gerrid species tend to stay at the breeding site, but can differ in dispersal via the water surface. Reproductive flightless females disperse most actively via the water surface, possibly bypassing the trade-off between dispersal and reproduction. One species has a sex-dependent dispersal pattern, with females being rather philopatric, whereas males often disperse. Three other gerrid species are highly dispersive and tend to change breeding site. V. caprai, the only lotic species included in this survey, tend to move upstream and possibly compensate for the downstream drift.

Las chinches acuáticas del infraorden Gerromorpha son especies adaptadas a caminar o patinar sobre la película superficial del agua principalmente en ambientes de agua dulce, sin embargo, algunas especies se han adaptado a vivir en ambiente marinos y actualmente no se cuenta con un inventario de la riqueza y composición de la fauna de chinches patinadoras marinas para el Neotrópico. A partir de la revisión bibliográfica, de los especímenes depositados en colecciones entomológicas y expediciones en campo, se obtuvieron los registros de chinches asociadas a ambientes marinos. A cada registro se les asignó una categoría de hábitat (estuarios/ manglares, lagunas formadas por arrecifes de coral, guarida de cangrejo en manglar, charcas formadas por las mareas, mar cerca de la costa, ambientes pelágicos) y su distribución geográfica actualizada. Se registran 203 especies a nivel mundial de Gerromorpha en ambientes asociados a ecosistemas marinos. Para el Neotrópico se registraron cinco familias, 13 géneros y 48 especies que representan el 23 % de las especies a nivel mundial. En orden de riqueza de especies la familia Gerridae tuvo la mayor con 22 especies distribuidas en tres géneros, seguida de Veliidae con 17 especies de cinco géneros, Mesoveliidae con seis especies y tres géneros, Hermatobatidae con dos especies y un género, y por último Hebridae con un género y una especie.

Five species of ocean skaters Halobates are the only insects that have successfully  colonized the ocean.  In the western Pacific Ocean, three species of Halobates, H. micans, H. sericeus and H. germanus, are known to occur over a wide area. We investigated the spatio-temporal features of Halobates during the three cruises of R/V Hakuho Maru in the western Pacific in 1994, 1995 and 1998. During these cruises, the area between latitudes 7o N - 22o N and longitudes 125o E - 150o E was surveyed in all cruises, and in this area H. germanus was absent while H. micans and H. sericeus were caught every year. In 1994 and 1995, H. micans was found almost to the exclusion of H. sericeus and in 1998 H. sericeus was found almost to the exclusion of H. micans, suggesting that these two species rarely co-occur, while their distribution ranges change temporally. We examined water surface temperature, prevailing winds and the El Nino event as possible factors responsible for the replacement of H. micans by H. sericeus in 1998. 0n the ocean surface, oceanic diffusion is constantly acting to disperse  Halobates in all directions. However, local distribution patterns of H. micans and H.  sericeus were highly clumped, suggesting that these species have the ability to aggregate against oceanic diffusion.

Los Heteroptera acuáticos y semiacuáticos presentan alta riqueza en el Pacífico de Colombia. Estudios sobre la biología, ecología y distribución geográfica y altitudinal son conocidos para algunas de las especies presentes tanto en ecosistemas litorales de aguas salobres como dulceacuícolas lénticos y lóticos. El objetivo de este estudio fue comparar tres comunidades de heterópteros acuáticos y semiacuáticos, de ecosistemas lóticos costeros del Pacífico de Colombia, con base en su composición, riqueza, diversidad y abundancia. Con el fin de alcanzar este objetivo se muestrearon tres áreas entre los 0 y 35 m de altitud sobre el nivel del mar del litoral Pacífico en Tumaco (departamento de Nariño): dos asociadas con hábitats lóticos permanentes de los ríos Mejicano y Caunapí y una tercera asociada con un arroyo de flujo lento en Candelillas. Se determinó la composición, riqueza, diversidad y abundancia de cada uno de los tres ecosistemas lóticos, la diversidad beta con base en el análisis de similitud de Jaccard y el valor de importancia de las especies por su abundancia. Se recolectaron 339 individuos pertenecientes a siete familias y 25 especies. Cada ecosistema presentó 11 especies y la familia más abundante en los tres fue Gerridae. La composición específica, la diversidad y la abundancia, tanto de géneros como de especies, difirieron entre los tres sistemas. La similitud entre los tres ecosistemas lóticos fue inferior al 20%. El ecosistema acuático con mayor diversidad en heterópteros, según el índice de Shannon-Wiener, fue el arroyo de Candelillas. En río Mejicano el género con mayor número de especies y de individuos fue Rhagovelia y la especie más abundante fue Telmatometra whitei; en río Caunapí el género con mayor número de especies y de individuos fue Rhagovelia y la especie más abundante fue Martarega lofoides; y en el arroyo de Candelillas el género con mayor número de especies y de individuos fue Rheumatobates y la especie más abundante fue R. peculiaris. La especie con mayor valor de importancia fue Telmatometra whitei. Los tres ecosistemas lóticos costeros estudiados presentaron diferente composición de especies de heterópteros y una estructura disímil en un rango altitudinal muy estrecho.

This is the first guide to the aquatic Heteroptera of Singapore and Peninsular Malaysia to be published as a series in the Raffles Bulletin of Zoology. The families Gerridae and Hermatobatidae are included. Gerridae, with 22 genera and 54 recorded species, are probably the commonest aquatic bugs in our regions whereas Herrnatobatidae, a monotypic family, is represented by only 2 species. We have provided lists of known local species of Gerridae and their habitats, a key to genera as well as keys to species where applicable. We have also included illustrations of representative species of each genus, some of the key characters used, and notes on biology and habitat.

Relatively few insects have invaded the marine environment, and only five species of sea skaters, Halobates Eschscholtz (Hemiptera: Gerridae), have successfully colonized the surface of the open ocean. All five species occur in the Pacific Ocean, H. germanus White also occurs in the Indian Ocean, whereas H. micans Eschscholtz is the only species found in the Atlantic Ocean. We sequenced a 780 bp long region of the mitochondrial cytochrome oxidase subunit I gene (COI) for a total of 66 specimens of the five oceanic Halobates species. Our purpose was to investigate the genetic variation within species and estimate the amount of gene flow betweenpopulations. We defined 27 haplotypes for H. micans and found that haplotype lineages from each of the major oceans occupied by this species are significantly different, having sequences containing five to seven unique base substitutions. We conclude that gene flow between populations of H. micans inhabiting the Atlantic, Pacific, and Indian Ocean is limited and hypothesize that these populations have been separated for 1 to 3 million years. Similarly, there may be limited gene flow between H. germanus populations found in the Pacific and Indian Ocean and between H. sericeus populations inhabiting thenorthern and southern parts of the Pacific Ocean. Finally, we discuss our findings in relation to recent hypotheses about the influence of oceanic diffusion on the distribution and population structure of oceanic Halobates spp.

The Madagascan material of the halobatine genus Eurymetra Esaki, 1926 (Hemiptera: Heteroptera: Gerridae: Halobatinae), which is deposited at the Natural History Museum Vienna, is revised. A close examination of "Eurymetra madagascariensis Poisson, 1945" revealed two new species, Eurymetra santamariae sp. nov. and Eurymetra papaceki sp. nov. A defi nition of the newly established Eurymetra madagascariensis species group is provided as well as keys to the freshwater halobatine genera and to Eurymetra species known from Madagascar. [ABSTRACT FROM AUTHOR]

Two new species of the genus Esakia Lundblad, 1933 are described, both from Borneo: Esakia borneensis sp. n. and E. mazzoldii sp. n. For the first time, E. johorensis Cheng, 1966 is reported from Sumatra; E. hungerfordi Miyamoto, 1967 from Sarawak and Sabah; and E. lundbladi Cheng, 1966 from Thailand (Narathiwat Province). The taxonomy of E. kuiterti Hungerford and Matsuda, 1958 and E. hungerfordi is discussed. Esakia hungerfordi, previously considered by Polhemus (1992) as a synonym of E. fernandoi, is treated here as a separate species from the latter. Easkia kuiterti, which was also synonymised with E. ventidioides Lundlblad, 1933 by Polhemus (1992), is considered valid species. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Aquarius lunpolaensis (Lin) from the late Oligocene of central Tibet is redescribed. • " Halobates bagonensis " should be interpreted as an exuvium of Aquarius lunpolaensis. • The extant Aquarius najas -group was much wider distributed in the late Oligocene. • The findings support the hypothesis that the elevation of central Tibet was low, some 25 million years ago. Abstract The semi-aquatic hemipteran family Gerridae (water striders), similar to other gerromorphan bugs, is a distinct group noted for their ability to walk on the surface of water, especially with respect to their locomotion, feeding, and behaviour. The three principal Holarctic gerrine genera, Aquarius Schellenberg, Gerris Fabricius and Limnoporus Stål, are important organisms for studies of biogeography, evolutionary trends and ecological adaptations of the Gerridae. Fossil gerrids are comparatively sparse, and direct fossil evidence elucidating the early diversification and biogeography of the extant widespread genus Aquarius remains elusive. Here we redescribe and reinterpret the extinct species Aquarius lunpolaensis (Lin, 1981) based on new well-preserved conspecific specimens from contemporaneous localities in the Lunpola and Nima basins of central Tibet, China. The new fossils confirm the placement of these fossils in Aquarius as evidenced by their large body size, first antennal segment longer than the following two segments combined, and well-developed abdominal connexival spines. The new discovery of a series of larval instars at different developmental stages confirms that " Halobates bagonensis " should be interpreted as an exuvium of the dominant species Aquarius lunpolaensis and demonstrates that the extant western Palaearctic najas -group had a much wider distribution in the late Oligocene (Chattian). The occurrence of an Aquarius water skater supports the hypothesis that the elevation of central Tibet was comparatively low, some 25 million years ago. [ABSTRACT FROM AUTHOR]

En la Reserva Natural Río Ñambi, ubicada en la vertiente del pacífico de los Andes de Colombia, región del Chocó biogeográfico, se estudió la composición de las chinches semiacuáticas. Dos familias Gerridae y Veliidae, cuatro géneros Potamobates, Charmatometra, Rhagovelia y Microvelia y doce especies fueron registradas. Rhagovelia fue el más diverso con cuatro grupos y nueve especies; se incluye una clave ilustrada para las especies de éste género, proporcionando notas sobre la distribución geográfica.

This paper includes a list of 62 species of Heteroptera (Nepomorpha and Gerromorpha), categorized into 12 families: Nepidae (2), Belostomatidae (1), Corixidae (25), Naucoridae (1), Aphelocheiridae (1), Notonectidae (6), Pleidae (1), Mesoveliidae (1), Hebridae (3), Hydrometridae (2), Velidae (9) and Gerridae (10). Two species are new for the fauna of Serbia: Hesperocorixa moesta (Fieber, 1848) and Velia (Plesiovelia) mancinii mancinii Tamanini, 1947. [ABSTRACT FROM AUTHOR]

Abstract The morphology and histology of the female reproductive system of Gerris lacustris water strider (Linnaeus 1758) (Heteroptera: Gerridae) are described using both light and scanning electron microscopy (SEM). Based on histomorphology, the adult female reproductive system of G. lacustris consists of a pair of ovaries, a pair of lateral oviducts, a common oviduct. The ovaries are connected to a genital aperture by oviducts. Each adult ovary is composed of four telotrophic meroistic type ovarioles. A peritoneal sheath is a thin membranous layer surrounding the entire ovariole. The ovarioles are attached to the dorsal wall of the anterior prothorax by terminal filaments. Each ovariole is divisible into four different regions: the thread like terminal filament followed by the germarium containing nurse cells (trophocytes) and the primordial oocytes, vitellarium containing oocytes at different developmental stages and pedicel (ovariolar stalk, calyx). A long vitellarium is developed composed of a series of oocytes in their folicular sheath. The vitellarium becomes progressively large towards the distal end and the pedicel, in which the mature eggs are lodged before passing into the short lateral oviduct. It opens to the common oviduct. [ABSTRACT FROM AUTHOR]

Highlights • Female water striders cannibalize juveniles at higher rates than males. • Single females increase refuge use in response to male presence. • Males decrease water use in the absence of alternative prey, decreasing sexual conflict, and allowing females to forage. • Juvenile water striders increase refuge use when female and male presence and activity on the water increases. Abstract To test the hypothesis that male harassment of females reduces adult female time spent on the water foraging (water use), and thus cannibalism by adult females on juveniles, we manipulated heterospecific prey availability, and social context in adult water striders and measured their effects on: 1) cannibalism of juveniles, 2) activity of adults and 3) habitat use of adults and juveniles. Cannibalism rarely occurred with alternative prey present, but was common without alternative prey. Without alternative prey, females cannibalized much more than males, but contrary to predictions, male presence did not reduce cannibalism rates. Male presence decreased female water use; however, this was counteracted by the fact that the lack of alternative prey increased female water use and activity while on the water. Furthermore, in groups of 4 males with 4 females, lack of alternative prey reduced male activity while on the water. Thus the predicted negative effect of sexual conflict on cannibalism was reduced by female and male responses to low food availability. Juveniles increased time off the water when more females or males were more on the water and active. Overall, cannibalism rates depended on alternative prey, male-female social dynamics, female foraging and juvenile refuge use. [ABSTRACT FROM AUTHOR]

Sexual conflict can lead to rapid and continuous coevolution between females and males, without any inputs from varying ecology. Yet both the degree of conflict and selection on antagonistic traits are known to be sensitive to local ecological conditions. This leads to the longstanding question: to what extent does variation in ecological context drive sexually antagonistic coevolution? In water striders, there is much information about the impacts of ecological factors on conflict, and about patterns of antagonistic coevolution. However, the connection between the two is poorly understood. Here, we first review the multiple ways in which ecological context might affect the coevolutionary trajectory of the sexes.We then review ecological and coevolutionary patterns in water striders, and connections between them, in light of theory and new data. Our analysis suggests that ecological variation does impact observed patterns of antagonistic coevolution, but highlights significant uncertainty due to the multiple pathways by which ecological factors can influence conflict and its evolutionary outcome. To the extent that water striders are a reasonable reflection of other systems, this observation serves as both an opportunity and a warning: there is much to learn, but gaining insight may be a daunting process in many systems. [ABSTRACT FROM AUTHOR]

Size‐assortative mating, defined as a positive linear association of body size between members of mating pairs, can arise from mechanical constraints on pairing efficiency, particularly when mating success is affected by males' mate‐grasping force. In this context, female resistance is predicted to have an important role in changing the threshold force necessary for males to hold females, thereby contributing to the effect of mechanical constraints. Thus, increased female resistance is expected to increase the paring success of an optimally sized male relative to the female body size (sexual size ratio = male body size/female body size = 0.86), which leads to positive size‐assortative mating. However, very little is known about the extent to which female resistance affects mechanical constraints on mate grasping. Here, using the water strider Gerris gracilicornis (Hemiptera: Gerridae), we tested whether the level of female resistance affected the relationship between the sexual size ratio and latency to pair. We found that optimally sized males mated sooner than other males when females resisted a male's mating attempts. When females did not resist, an effect of sexual size ratio on latency to pair was not found. Our results thus imply that increased female resistance to male mating attempts may strengthen the pattern of size‐assortative mating. We provide clear empirical evidence that female resistance to mating influences the effect of mechanical constraints on size‐assortative mating under sexual conflict. This result further suggests that patterns of size‐assortative mating can be altered by a variety of ecological circumstances that change female resistance to mating in many other animal species under sexual conflict. Relationship between a range of male body size relative to female body size (sexual size ratio) and threshold force (dotted lines) necessary for males to successfully grasp females at the initiation of mating. The threshold force is high when females resist more, and there is a narrowing of the optimal male size range (relative to a certain female size) that leads to a successful initiation of mating. This is expected to result in a strong size‐assortative mating pattern. [ABSTRACT FROM AUTHOR]

The genus Cylindrostethus Mayr, 1865 from India is studied. Prior to this study C. productus (Spinola, 1837) and C. scrutator (Kirkaldy, 1899) of Cylindrostethus were known from India. The record of C. scrutator (Kirkaldy, 1899) from India is doubtful. Study of gerrid specimens from Andaman Islands revealed one more additional species, C. costalis costalis Schmidt, 1915 new to Indian fauna. So, presently two species of this genus are known from India namely C. costalis costalis and C. productus, both belonging to the C. costalis species group (Polhemus 1994). A detailed study has been made of the male and female genitalia of Cylindrostethus known from India. [ABSTRACT FROM AUTHOR]

There exist surprisingly few marine insects, most of which are confined to the intertidal zone. Halobates is the only genus to have some oceanic species along with some coastal species. Among the coastal sea skaters, that is, genus Halobates and its close relative, genus Asclepios, there are variations in their affinity for the shore. We have studied the distributions of two endangered Japanese sea skaters, Halobates matsumurai and Asclepios shiranui in Kujukushima, where they cooccur in coves. To compare their survival strategies at sea, we especially noted differences in their distributions along the shore during high and low tides. The results show that A. shiranui tended to remain along the shore during low tide. This species appeared to cling to the shore against the ebb current and to stay in the protected coves. By contrast, H. matsumurai tended to leave the shore during low tide. Notably, some adults were found skating outside the coves. The strategy of H. matsumurai appeared to be leaving with the ebb current even beyond the coves, thereby using more resources and enlarging its habitat. Some such coastal Halobates might have acquired the ability to live on the open ocean clearly independent of the shoreline. [ABSTRACT FROM AUTHOR]

Abstract: Aim: Palaeoclimatic and palaeogeological events have been identified as two main factors that influence the genetic structuring of extant organisms. We studied a montane stream‐dwelling insect, Metrocoris sichuanensis, to explore the relative roles played by these two factors in population genetic connectivity. Location: Sichuan Basin, China. Methods: Mitochondrial (COI, COII, Cytb, 16S) and nuclear (EF‐1α, ITS1) markers were sequenced from 208 individuals. Suitable habitat shifts from the Last Glacial Maximum (LGM) to the present were predicted through fine‐tuned ecological niche modelling (ENM). Phylogenetic and phylogeographical analyses were conducted to reveal the population genetic structure. Intraspecific divergence and expansion times were estimated using beast. Finally, the least cost path (LCP) method coupled with migrate analysis was used to identify possible dispersal corridors and estimate the asymmetric gene flow. Results: Our ENM results suggested that population habitat connectivity did not change both in the LGM and current conditions. Whole haplotypes were separated into four highly supported clades/haplogroups that exhibited strong geographical structure. The splitting events between the four lineages likely date back to the Early Pleistocene. Bayesian skyline plot (BSP) indicated a moderate demographic growth from the LGM to the present. A putative dispersal corridor was detected along the Longmen Mountains thrust belt, with unidirectional gene flow from north to south. Main conclusion: Our findings support the geographical isolation of the genetic lineages and a deep early Pleistocene split in M. sichuanensis. Landscape connectivity analysis incorporating the genetic data and the ENM prediction revealed that population genetic connectivity was strongly associated with stable climatic habitats shaped by complex topography. The drainage system might have assisted the rapid movement of populations along the Longmen Mountains thrust belt. A strategy for researching the population genetic connectivity of narrow endemics, such as M. sichuanensis, in global biodiversity hotspots is proposed and discussed in this paper. [ABSTRACT FROM AUTHOR]

Heat coma temperatures (HCTs) and super cooling points (SCPs) were examined for nearly 1000 oceanic sea skaters collected from in the Pacific and Indian Oceans representing four Halobates species; H. germanus, H. micans, H. sericeus, and H. sp. Analysis was conducted using the entire dataset because a negative correlation was seen between the HCTs and SCPs in all four species. A weak negative correlation was seen between HCTs and SCPs with a cross tolerance between warmer HCTs and colder SCPs. The weakness of the correlation may be due to the large size of the dataset and to the variability in ocean surface temperature. The negative correlation does however suggest that oceanic sea skaters may have some form of cross tolerance with a common physiological mechanism for their high and low temperature tolerances. [ABSTRACT FROM AUTHOR]

Some of the strongest examples of a sexual 'arms race' come from observations of correlated evolution in sexually antagonistic traits among populations. However, it remains unclear whether these cases truly represent sexually antagonistic coevolution; alternatively, ecological or neutral processes might also drive correlated evolution. To investigate these alternatives, we evaluated the contributions of intersex genetic correlations, ecological context, neutral genetic divergence and sexual coevolution in the correlated evolution of antagonistic traits among populations of Gerris incognitus water striders. We could not detect intersex genetic correlations for these sexually antagonistic traits. Ecological variation was related to population variation in the key female antagonistic trait (spine length, a defence against males), as well as body size. Nevertheless, population covariation between sexually antagonistic traits remained substantial and significant even after accounting for all of these processes. Our results therefore provide strong evidence for a contemporary sexual arms race. [ABSTRACT FROM AUTHOR]

Eotrechus fuscus sp. nov. (Hemiptera: Heteroptera: Gerridae: Eotrechinae) is described from Sikkim, Himalaya, India and compared with all known congeners. The male genitalia study was undertaken to confirm validity of this species. Eotrechus longipes Andersen, 1982 is recorded from Sikkim for the first time. A key to all known Indian species is also provided. With the addition of this new species, a total of six species of this genus are currently reported from India. [ABSTRACT FROM AUTHOR]

Aquatic and semiaquatic heteropterans present high richness in the Colombian Pacific Region. Studies about biology, ecology, as well as geographical and altitudinal distribution have provided a great amount of data about some species inhabiting brackish waters, as well as lentic and lotic freshwaters. Based on that, the aim of this study was to compare three communities of aquatic and semiaquatic heteropterans of lotic freshwater ecosystems from the Pacific coastal region in Colombia based on species composition, richness, diversity and abundance. In order to meet this objective, sites were sampled at altitudes ranging from 0 and 35 m of altitude above sea level in the Pacific littoral in Tumaco (Department of Nariño): two sites were located in permanent lotic ecosystems in the Mejicano and Caunapí rivers and a third site was located in a slow-flow intermittent stream in Candelillas. The composition, richness, diversity and abundance for each ecosystem, as well as the beta diversity on the basis of the Jaccard similarity coefficient and the value of importance of species for abundance were determined. A total of 339 individuals, seven families and 25 species were recorded. Each ecosystem presented 11 species, with Gerridae the most abundant family in the three ecosystems. Differences between the specific composition, diversity and abundance of the three ecosystems, in terms of genera and species, were determined. The similarity between the three aquatic ecosystems was lower than 20%. The intermittent stream in Candelillas was the aquatic ecosystem with the greatest diversity of heteropterans, according to the index of Shannon-Wiener. In the Mejicano River, Rhagovelia was the genus with a greatest number of species and individuals, and Telmatometra whitei was the most abundant species. In the Caunapí river, Rhagovelia was the genus with the greatest number of species and individuals and Martarega lofoides was the most abundant species. In the intermittent stream in Candelillas, Rheumatobates was the genus with the greatest number of species and individuals, and R. peculiaris was the most abundant species. The species with the highest Importance Value Index was Telmatometra whitei. The three coastal lotic ecosystems presented different compositions of heteropteran species and dissimilar structure over a very narrow altitudinal range. [ABSTRACT FROM AUTHOR]

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