Annotated checklist of Iranian Hydrophilidae (Coleoptera: Polyphaga: Hydrophiloidea)

This checklist comprises all species of Hydrophilidae (Coleoptera: Hydrophiloidea) quoted in the literature referring to Iran and confirmed by our study. In total, 104 species within 17 genera and five subfamilies, Hydrophilinae (eight genera, 63 species), Chaetarthriinae (three genera, five species), Enochrinae (single genus, 20 species), Acidocerinae (single genus, three species) and Sphaeridiinae (four genera, 13 species), are listed for the fauna of Iran. Three species are endemic; four species are recorded here for the first time from Iran, and nine species are excluded from Iranian fauna.     

Colonization under threat of predation: avoidance of fish by an aquatic beetle, Tropisternus lateralis (Coleoptera: Hydrophilidae)

Documenting the role of past interactions in the assembly of present communities has proven problematic. Colonization is a key process in community assembly that is both potentially driven by past interactions and amenable to experimental approaches. Colonization and oviposition by an aquatic beetle (Tropisternus lateralis) was assayed in the presence and absence of both 'harmless' and tactilely/visually isolated predatory fish (Lepomis gibbosus and L. macrochirus). Beetles avoided each treatment with fish when compared to fish-free experimental pools. Activity levels after colonization also differed significantly between adults in fish and fish-free tanks. Predator effects on species composition are typically ascribed to contemporary predation events; the presence of a strong avoidance response demonstrates that past species interactions affect present distributions and may play an important role in the ongoing assembly of contemporary communities. Documentation of such avoidance behavior in a growing number of species fundamentally alters our view of the processes affecting species distributions and the process of community assembly.     

Immature Stages of Hydrobiomorpha spinosa (Orchymont, 1928) (Coleoptera: Hydrophilidae)

The preimaginal stages of the Neotropical species Hydrobiomorpha spinosa (Orchymont) are described and figured for the first time. They are compared to the larvae of the New World species Hydrobiomorpha casta (Say) and to unidentified African and Australian larvae. Bionomical notes on this species are included.     

New water scavenger beetles (Coleoptera: Hydrophilidae) from the mesozoic of Mongolia

A new genus and two new species of water scavenger beetles, Hydrophilopsia bontsaganica, sp. nov. and Prospercheus cristatus, gen. et sp. nov., are described from the Upper Jurassic and Lower Cretaceous of Mongolia. The systematic position of the new genus is discussed.     

中国牙甲科三新记录种

报道采自新疆的我国首次发现的牙甲科昆虫3种,直缘隆胸牙甲Paracymus aeneus(Germar)、褐苍白牙甲Enochrus fuscipennis(Thomson)、暗须苍白牙甲Enochrus testaceus Fabricius,研究标本保存于中山大学生物博物馆.     

中国牙甲科二新记录种

报道我国南方牙甲科2新记录种:锚丽阳牙甲Helochares atropiceus Régimbart和线纹梭腹牙甲Cercyon lineolatus(Motschulsky)。     

Digestive proteinases of the larger black flour beetle, Cynaeus angustus (Coleoptera: Tenebrionidae)

Digestion in the larger black flour beetle, Cynaeus angustus (LeConte), was studied to identify new control methods for this pest of stored grains and grain products. The physiological pH of the larval gut, as measured with extracts in water, was approximately 6.1, and the pH for optimal hydrolysis of casein by gut extracts was 6.2 when buffers were reducing. However, under non-reducing conditions, hydrolysis of casein and synthetic serine proteinase substrates was optimal in alkaline buffer. Three major proteinase activities were observed in zymograms using casein or gelatin. Caseinolytic activity of C. angustus gut extracts was inhibited by inhibitors that target aspartic and serine proteinase classes, with minor inhibition by a cysteine proteinase inhibitor. In particular, soybean trypsin and trypsin/chymotrypsin inhibitors were most effective in reducing the in vitro caseinolytic activity of gut extracts. Based on these data, further studies are suggested on the effects of dietary soybean inhibitors of serine proteinases, singly and in combination with aspartic and cysteine proteinase inhibitors, on C. angustus larvae. Results from these studies can be used to develop new control strategies to prevent damage to grains and stored products by C. angustus and similar coleopteran pests.     

Comparative Studies on the Developmental Stages of Three Species of Tropisternus (Coleoptera: Hydrophilidae)

The egg cases, eggs, and different stages of life cycles of Tropisternus lateralis (Fabricius), T. blatchleyi D'Orchymont, and T. collaris (Fabricius) are described. A table is given for separating the various developmental stages of the three species.     

Comparative Life Histories of Three Species of Tropisternus in the Laboratory (Coleoptera: Hydrophilidae)

Three species of Tropisternus (T. lateralis nimbatus) [SAY], T. collaris [subspecies] [FABRICIUS], and T. blatchleyi modestus [D'ORCHYMONT] have been reared in the laboratory over a period of several years for determination of the genetics of their color patterns and various physiological studies. Methods of rearing and handling are discussed, and the behavior, duration of life history stages, and general biology of adults and immature stages are summarized.     

The population metabolism and life history tactics of Neobisium muscorum (Leach) (Arachnida: Pseudoscorpiones)

Summary The population metabolism of N. muscorum at a beechwood site in southern England was determined for two separate year periods by two methods; a detailed computer analysis and a best estimate. These methods, which are based on data of biomass, population dynamics, field temperatures, and respiration rates of all life stages with temperature, are compared. The validity of extrapolating laboratory determined basal metabolic rates to field activity is discussed; and the population metabolism of N. muscorum is compared with that reported for other soil and litter invertebrate species, both predatory and non-predatory.The metabolic rates of the adults of a second species of pseudoscorpion found at the beechwood site (Chthonius orthodactylus (Leach)), were determined, and the life cycle and metabolism of this species is compared to N. muscorum. The influence of low environmental temperatures on poikilothermic predators, with reference to life cycle strategies, basal metabolism and geographic distribution, is discussed.     

The unusual life history of a southern Iberian Peninsula population of Torleya major (Ephemeroptera: Ephemerellidae)

Abstract The nymphal biology of a population of Torleya major (Klapálek) in southern Iberian Peninsula was studied. An atypical life cycle pattern is described, with eggs hatching in August producing a fast‐developing cohort with adults emerging in autumn and a second slow‐developing cohort with adults emerging in spring of the following year. Nymphal growth occurred primarily in summer–autumn (in the first cohort) and in spring (in the second). The origin of such a life history is discussed. Nymphs were collector‐gatherers, consuming mainly detritus. Although ontogenetic shifts on the use of trophic resources were detected, similar food was utilized during the months when both cohorts cohabited, eliminating the possibility that the rapid growth of the first cohort could be related to the utilization of different food resources.     

Description of the Immature Stages of Three Nearctic Species of the Genus Berosus Leach (Coleoptera: Hydrophilidae)

Egg cases, larvae, and pupae of Berosus corrini Wooldridge 1964, Berosus hoplites Sharp 1887, and Berosus pugnax LeConte 1863, are described and illustrated with line drawings. Bionomic and behavioral observations of larvae and adults are included. Keys to different instars of B. hoplites and B. pugnax larvae are provided.     

Novel molecular identification methods for the larger black flour beetle,Cynaeus angustus (Coleoptera: Tenebrionidae)

Two new methods were developed for identifying Cynaeus angustus (LeConte) (Coleoptera: Tenebrionidae) by DNA amplification using simplex and real-time PCR targeting the cytochrome c oxidase subunit I (COI) sequence reported previously. The specificities of the PCR primers and probe were also confirmed by the two PCR methods using the 22 main stored-product insect species, including DNA samples from nine tenebrionid beetle species. The results showed that the newly developed simplex and real-time PCR-based methods have sufficient specificity for analysis. The limits of detection for C. angustus total DNA by the simplex and multiplex PCR were 320 fg and 20 pg, respectively.

     

The life history of the diving beetle, Lancetes angusticollis (Curtis) (Coleoptera: Dytiscidae), on sub-Antarctic South Georgia

Two populations of the world's most southerly diving beetle (Lancetes angusticollis) were studied on sub-Antarctic South Georgia between November 1995 and April 1996. Parallel observations were made on laboratory cultures of each life stage. All juvenile stages of L. angusticollis are voracious predators, preying mainly on the herbivorous copepod Boeckella poppei. Adult beetles additionally predate benthic ostracods. Laboratory predation rates and field population densities found in this study suggest that L. angusticollis has a more significant impact on its prey than recognised in recent studies of South Georgian lakes. Spring field samples contained only a few individuals of larval instar IV and adults. Young larvae were present from December onwards, with a rapid progression through juvenile instars during the summer months. Fourth instar larvae left the water for pupation between mid-December and at least mid-February. Combining these observations with known developmental threshold temperatures for each life stage implies that L. angusticollis has a complex biennial (minimum) life-cycle, with overwintering possible in three life stages [aquatic larvae, terrestrial pupae (not proven) and aquatic adults]. L. angusticollis may be a suitable indicator species in the context of climate warming studies: a small (1°C) rise in mean environmental temperatures, comparable to that already observed at several sub-Antarctic and maritime Antarctic localities, would allow completion of an annual (univoltine) life-cycle, with concomitant rapid population increase, and serious implications for trophic interactions in these simple lake ecosystems. Received: 24 November 1997 / Accepted: 12 April 1998     

Revision of the genus Psalitrus d'Orchymont from Southern India and Sri Lanka (Coleoptera: Hydrophilidae: Omicrini)

Abstract. Eight new species of Psalitrus are described: P.besucheti, P.coccinelloides, P.decoratus and P.silvestris from Southern India and P.loebli, P.mahanuwara, P.serendibensis and P.veddha from Sri Lanka. The two Psalitrus known previously from India, P.championi and P.fallax , are redescribed and lectotypes and paralectotypes are designated. For each species the aedeagus and female ectodermal genitalia are figured. For the first time among Hydrophiloidea species characters have been found in female ectodermal genitalia, thanks to staining with chlorazol black dye. The best biometric characters are selected by multiple-discriminant analysis and an identification key is given. A list of the known Psalitrus species is given.