Sexual Selection on Accessory Glands, Genitalia and Protarsal Pads in the Whirligig Beetle Dineutus nigrior Roberts (Coleoptera: Gyrinidae)

Sexual selection is a potent force in the evolution of morphology in sexually reproducing species. When large size in a trait is favored by sexual selection the trait often exhibits positive allometry. Mating behavior in whirligig beetles consists of males attempting to grasp reluctant females using enlarged protarsi (protarsal pads). Here we use allometry and a mating experiment to investigate sexual selection pressures on accessory glands, intromittant genitalia (aedeagus), and protarsal pads in males of the whirligig beetle Dineutus nigrior Roberts. Accessory gland size exhibited positive allometry and males with larger accessory glands were more likely to copulate suggesting that larger size in this trait is favored by sexual selection. Males with larger accessory glands attempted to copulate more often but did not exhibit fewer failed mating attempts before copulating. This suggests that the increased probability of mating in males with large accessory glands is due to higher mating attempt frequency and not to increased ability to overcome female resistance. The length of the aedeagus exhibited negative allometry and males with a longer aedeagus did not have increased mating success. This is consistent with stabilizing selection favoring an intermediate size in this trait. The allometric slope of the protarsal pad did not differ from isometry and males with larger protarsal pads did not have increased mating success. This suggests that larger protarsal pads are not favored by sexual selection.     

In or Out-of-Madagascar?—Colonization Patterns for Large-Bodied Diving Beetles (Coleoptera: Dytiscidae)

High species diversity and endemism within Madagascar is mainly the result of species radiations following colonization from nearby continents or islands. Most of the endemic taxa are thought to be descendants of a single or small number of colonizers that arrived from Africa sometime during the Cenozoic and gave rise to highly diverse groups. This pattern is largely based on vertebrates and a small number of invertebrate groups. Knowledge of the evolutionary history of aquatic beetles on Madagascar is lacking, even though this species-rich group is often a dominant part of invertebrate freshwater communities in both standing and running water. Here we focus on large bodied diving beetles of the tribes Hydaticini and Cybistrini. Our aims with this study were to answer the following questions 1) How many colonization events does the present Malagasy fauna originate from? 2) Did any colonization event lead to a species radiation? 3) Where did the colonizers come from—Africa or Asia—and has there been any out-of-Madagascar event? 4) When did these events occur and were they concentrated to any particular time interval? Our results suggest that neither in Hydaticini nor in Cybistrini was there a single case of two or more endemic species forming a monophyletic group. The biogeographical analysis indicated different colonization histories for the two tribes. Cybistrini required at least eight separate colonization events, including the non-endemic species, all comparatively recent except the only lotic (running water) living Cybister operosus with an inferred colonization at 29 Ma. In Hydaticini the Madagascan endemics were spread out across the tree, often occupying basal positions in different species groups. The biogeographical analyses therefore postulated the very bold hypothesis of a Madagascan origin at a very deep basal node within Hydaticus and multiple out-of-Madagascar dispersal events. This hypothesis needs to be tested with equally intense taxon sampling of mainland Africa as for Madagascar.     

Mechanisms Modeling the Double Rotation of the Elytra in Beetles (Coleoptera)

We recorded transient movements,i.e.opening and closing,of beetle elytra.The beetles were tethered from below and filmed under a skew mirror; two markers were glued on each elytron at the apex and at the base.Body-fixed 3D traces of the apical and basal markers were reconstructed.The trace of the basal marker was,as a rule,non-parallel to the apical trace.The costal edge of the elytron uniformly supinated in the course of adduction of the apical marker.We found two essential attributes of double rotation:(1) the elytron to body articulation is approximately a spherical mechanism; (2) transient opening and closing possess single degree of freedom.The double rotation was modeled with two mechanisms:(1) a flexagon model of the Haas and Wootton's type simulated the elytral movement relative to the movement of one facet of the flexagon; (2) a screw and nut model provided traces as two sectors of a helical thread,one sector was phase shifted with respect to other one.Screw guideways in a spherical mechanism give rise to discrepancies.Exact solution for a spherical mechanism with two guideways was proposed.The modeling revealed the attribute (3):the elytron is actuated by two linked but differently directed drives.Experimental investigations on the elytron to body articulation may be oriented at search of those mechanisms.     

On the systematic position of the family Gyrinidae (Coleoptera: Adephaga)

Various characters of adult and larval members of Adephaga and Cupedidae were analyzed, and suggest that Gyrinidae are the sister-group of the remaining Adephaga, and are not closely related to the remaining aquatic Adephaga. The aquatic families Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae seem to form a well founded monophyletic unit. The following characters are considered as synapomorphies of Adephaga excluding Gyrinidae: bifurcate condition of the muscle (= M.) tentoriopraementalis inferior, reduction of hypopharynx, strongly developed prosternal process, reduction in size and specialized modification of the ventral sclerite of the mesothorax, strongly developed mesofurcal arms, a high mesopleural ridge, globular mesocoxae restricted to rotatory movements, invaginated sternum VIII (coxostemum), the strongly curved base of the median lobe of the aedeagus, which articulates with the parameres, the rotated position of the aedeagus in repose, fusion of the larval clypeolabrum with the frons and reduction of the larval lacinia. Mesal shifting of M. episterno-coxalis prothoracis, and the fusion of the apical portions of the malpighian tubules of either side are considered as synapomorphies of Adephaga excluding Rhysodidae and Gyrinidae. Lateral reduction of the meta “sternal” transverse ridge and the presence of the subcubital setal binding patch of the hind wing are considered as synapomorphic characters of Trachypachidae, Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae. We postulate that the metacoxal fusion occurred independently in gyrmids and the common ancestor of Trachypachidae, Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae. Consequently we consider this character state as another synapomorphy of Trachypachidae and Hydradephaga excluding Haliplidae and Gyrinidae. The following characters are considered as synapomorphies of Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae: Loss of tactile setae on the head capsule, metafurcal origin on the intercoxal wall, expansion of the intercoxal wall, elongation of the subcubital setal binding patch, loss of Mm. furca-coxale anterior and posterior, reduction of the larval abdominal segments IX and X, and the shifting of the uropmphi onto the ventral side of segment VIII. Presence of M. tentorio-mandibularis and M. stipitopalpalis intemus are certainly primitive features of adult gyrinids but the distribution of these character states among most members of Adephaga is yet unclear. Chemical defence gland constituents point towards a very isolated position of Gyrinidae. The old age of the group, documented by a larva found in upper Permian deposits, may support the hypothesis of a sister-group relation-ship between Gyrinidae and the remainder of Adephaga.     

A taxonomic review of the Gyrinidae (Coleoptera) in Korea

A taxonomic review of Korean Gyrinidae is presented. Seven species [Dineutus orientalis (Modeer, 1776), Gyrinus gestroi Régimbart, 1883, Gyrinus japonicus Sharp, 1873, Gyrinus pullatus Zaitzev, 1908, Orectochilus punctipennis Sharp, 1884, Orectochilus Regimbarti Sharp, 1884 and Orectochilus villosus (Müller, 1776)] in three genera are recognized, one of which (Orectochilus punctipennis Sharp, 1884) is reported for the first time in Korea. We also found that Gyrinus curtus Motschulsky, 1866 previously recorded in Korea was an incorrect identification of Gyrinus pullatus Zaitzev, 1908. Habitus and SEM photographs, distribution maps, keys, and diagnoses of genera and species are provided.     

A review of the genus Berosus Leach of Cuba (Coleoptera,Hydrophilidae)

The Cuban fauna of the genus Berosus Leach, 1817 is reviewed based on newly collected material as well as historical and type specimens. Nine species are recognized, including three recorded from Cuba for the first time: Berosus infuscatus LeConte, 1855, Berosus interstitialis Knisch, 1924 (= Berosus stribalus Orchymont, 1946 syn. n.) and Berosus metalliceps Sharp, 1882. Only one of the nine Cuban species, Berosus chevrolati, remains endemic to Cuba, as two other species previously considered as endemic to Cuba are recorded from elsewhere: Berosus quadridens from Mexico and Central America and Berosus trilobus from the Dominican Republic. Notes on biology and Cuban distribution are provided for all nine species. Berosus quadridens Chevrolat, 1863, stat. restit. is removed from synonym with Berosus truncatipennis and considered a valid species.     

Larval morphology and chaetotaxy of Macrogyrus oblongus (Boisduval, 1835) (Coleoptera: Gyrinidae)

The larvae of the grooved whirligig beetle Macrogyrus oblongus (Boisduval, 1835) are described and illustrated including detailed morphometric and chaetotaxic analyses of selected structures. Larvae of Macrogyrus Régimbart, 1882 Régimbart, M. (1882), ‘Essai Monographique de la Famille des Gyrinidae. 1re partie’, Annales de la Société entomologique de France, 51, 379–458. [Google Scholar] exhibit the characters traditionally recognised as autapomorphies of the Gyrinidae. The first instars bear egg bursters on the parietal, a potential additional autapomorphy. Putative larval autapomorphies of the tribe Dineutini are the presence of additional setae on the mandible, the absence of the seta TR2, and the presence of pore-like additional structures on the ultimate palpomeres. Macrogyrus larvae differ from those of the other known dineutine genera (Andogyrus Ochs, 1924 and Dineutus MacLeay, 1825) in the absence of a neck constriction and in the distal position of the pore LAc. Other useful characters to distinguish genera within Dineutini are the presence or absence of additional setae on the cardo and coxa, and the posterior margin of the lacinia dentate or smooth.     

Diving Beetles of the Genus Rhantus in Costa Rica: Taxonomy and Biogeography,with Notes on South American Species (Coleoptera: Dytiscidae)

We describe Rhantus bohlei sp.n. from Costa Rican highlands. This is the fourth Rhantus species known from Costa Rica, besides of Rhantus souzannae Balke, R. gutticollis (Say) and R. calidus (F.). The latter two are wider spread, the others are endemic to Costa Rican highlands. Endemicity of the fauna is 50% (Canada: 7 species, endemicity 0). We suggest that the Costa Rican Rhantus fauna is a mixture of Laurasian and Gondwanian elements. Here, new records for the South American species Rhantus crypticus Balke and R. franzi Balk e are provided.     

A revision and phylogenetic analysis of Stoiba Spaeth?1909 (Coleoptera,Chrysomelidae)

Stoiba Spaeth, 1909 is revised with a phylogenetic analysis of 38 adult morphological characters for nine Stoiba species and 11 outgroup species (Mesomphaliini, Ischyrosonychini, and Hemisphaerotini). Four Cuban species of Stoiba were not sampled. Parsimony analysis located the four most parsimonious trees. The strict consensus (CI=0.59, RI=0.78, Steps=83) resolved the monophyly of Stoiba. The monophyly of Stoiba is supported by pale yellow antennae, antennomere VII broader than its length, and rounded basal line of pronotum. An illustrated key to ten species of Stoiba is provided along with a distribution map of 11 species. Stoiba rufa Blake is synonymized with Stoiba swartzii (Thunberg) by a morphological comparison which includes female genitalia.     

Some Adaptive Features in the Respiratory System of Dineutes indicus Aubé (Coleoptera, Gyrinidae)

The spiracular structure characterized with a system of snarling dense outgrowths, has been studied in order to elucidate their reinterpreted role in respiration. The tracheal anatomy has undergone modifications to subserve a secondary function of reducing the metabolic heat in the thorax—a region of relatively high metabolic activity. Tracheation is so arranged as to enable this insect to lead successfully an amphibious existence. The rate of its oxygen consumption and its capacity to remain under water with an air bubble which functions as an efficient physical gill with temperature as an important limiting factor has been studied. Attempts have been made to analyse the anatomy of the respiratory system with reference to the insect's behaviour in its environment.     

A revision of the Cautires obsoletus species group from Java (Coleoptera,Lycidae)

The Javanese fauna of the species group Cautires obsoletus is revised. Altogether, eight Javanese species were classified in the group; five of them are proposed to be junior subjective synonyms: Cautires fruhstorferi Dudkova & Bocak, 2010, a replacement name of Bulenides lineatus Pic, 1921, Cautires javanicus Bourgeois, 1883, Cautires inhumeralis (Pic, 1921), Cautires nigromaculatus (Pic, 1925), and Cautires pudicus (Kleine, 1931) (all synonymized to Cautires obsoletus Waterhouse, 1879). Three Javanese species are redescribed: Cautires apicalis (Pic, 1925), Cautires obsoletus (Waterhouse, 1878), and Cautires singularithorax (Pic, 1925). Cautires apicalis (Pic, 1925) is removed from the synonymy of Cautires corporaali (Pic, 1921) and reinstated as a valid name. Three new species are proposed: Cautires walteri sp. n., Cautires taoi sp. n., and Cautires sukosarensis sp. n. All species are keyed and principal diagnostic characters are illustrated. The distribution and relationships to Cautires fauna of other Great Sundas islands are briefly discussed.     

On the thoracic anatomy of the Madagascan Heterogyrus milloti and the phylogeny of Gyrinidae (Coleoptera)

Gyrinidae is a group of beetles with a unique specialization of swimming on the water surface. Heterogyrus milloti Legros (Heterogyrinae) from Madagascar is a species with various preserved plesiomorphic features. The information on the morphology and biology was very limited until recently, and the thoracic anatomy remained largely unknown. Consequently, the aim of the present study is to describe external and internal thoracic features of Heterogyrus Legros in detail and to interprete them with respect to their phylogenetic and functional significance, with a special focus on the unusual flight apparatus of Gyrinidae. Characters documented with innovative techniques are compared to conditions found in other gyrinid genera and other groups of Adephaga, including characters of other body parts and larvae. A data matrix with 144 characters of adults, larvae and eggs was compiled and analysed cladistically. Gyrinidae excluding Spanglerogyrus Folkers (Heterogyrinae + Gyrininae) is supported by many apomorphies, mainly by a unique locomotor apparatus with paddle‐like middle and hind legs. The results confirm Heterogyrus as the earliest diverging branch in Gyrinidae except Spanglerogyrus, implying a sister‐group relationship between this genus and Gyrininae, a clade comprising Gyrinini, Dineutini and Orectochilini. The presence of an opening between the mesanepisternum and elytra, reduction of the lateral metafurcal arms, loss of the metathoracic M. furcacoxalis lateralis, and modifications of the head, including the dorsal shift of the upper subcomponent of the compound eyes, are synapomorphies of the three tribes. The monophyly of Gyrinini is moderately well‐supported, whereas Orectochilini is strongly supported by different characters including a highly simplified but functioning flight apparatus. A clade comprising Orectochilini and the dineutine genera is suggested by synapomorphies of adults and larvae. The monophyly of Dineutini was supported in a recent study, but not by the characters analysed here. Features of adults, larvae and eggs indicate that Gyrinidae are the sister group to the remaining adephagan families, as suggested in some earlier morphology‐based studies and recent analyses of large molecular datasets.     

Susceptibility of Sap Beetles (Coleoptera: Nitidulidae) to Entomopathogenic Nematodes

Nitidulid beetles (Coleoptera) are considered to be serious pests of date palms throughout the world. They attack ripe fruit, causing it to rot, and damage is reflected in both reduced yield and lower fruit quality. The present study was aimed at an evaluation of the susceptibility to different sap beetles to entomopathogenic nematodes. We further tested nematode efficacy in pots filled with soil infested by third instar larvae of the two beetle species. In Petri dish assay, mortality levels of Carpophilus humeralis and C. hemipterus exposed to Heterorhabditis sp. IS-5 strain indicated that the latter is less susceptible to nematode infection. Exposure of both sap beetle species to different nematode strains gave moderate levels of mortality (35-65%) with the heterorhabditid strains HP88, IS-5 and IS-25. The IS-12 strain of Heterorhabditis sp. showed poor virulence (<35% mortality) against larvae of C. humeralis as well as larvae and pupae of C. humipterus. The nematode species S. riobrave showed moderate virulence (35-65%) mortality to larvae and pupae of S. humeralis as well as to larvae of C. hemipterus . Exposure of C. hemeralis to different concentrations of Heterorhabditis sp. IS-5 in pots containing soil resulted in high mortality (>65%). In contrast, the lower concentrations (500 and 1000 nematodes/pot) caused low mortality (35%) of C. hemipterus . Other heterorhabditid strains caused 95-100% mortality of C. humeralis in pot assay. The HP88 strain of H. bacteriophora and the Tx strain of Steinernema riobrave showed poor effectiveness. Incubation of different nematode strains with the C. humeralis larvae at high temperature (32 C) resulted in an increase in insect mortality with the IS-12 and IS-21 strains. Reduced mortality was recorded with the HP88 strain treatment at the higher temperature. The IS-5 and IS-12 strains were equally effective in all three soil types tested, whereas the IS-19 strain was more effective in the Almog type soil than in the others.     

Beetles (Insecta: Coleoptera) as bioindicators of the assessment of environmental pollution

Bioindicators have been generating great interest in environmental pollution research. Insects and especially arthropod are useful to assess the effects of anthropogenic activities on the terrestrial ecosystem, because they are inclose contact with toxic elements present in soil and in leaf litter. Beetles are extremely sensitive to several ecological parameters, react quickly to environmental modifications and can be easily and cost-effectively sampled by various methods. These criteria make beetles excellent indicators of terrestrial ecosystem. In order to evaluate the environmental impact of human activities on different ecosystems, the use of Coleoptera in ecological studies has been largely increased in recent years.

This review presents the results obtained by researchers when using beetles as bioindicators of metallic pollution and forest disturbance.     

Two new species and new records of the genus Spinolyprops Pic, 1917 from the Oriental Region (Coleoptera,Tenebrionidae, Lupropini) *

Two new species of the genus Spinolyprops Pic, 1917 (Tenebrionidae, subfamily Lagriinae Latreille, 1825) are described from Thailand and China (Spinolyprops cribricollis sp. n., Spinolyprops thailandicus sp. n.). The species characters within the genus are discussed, photographs of all seven Oriental species are added, a species key for the Oriental species is compiled, and a map with the distributional patterns is provided.     

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.     

Taxonomic revision of the genus Callimerus Gorham s. l. (Coleoptera,Cleridae). Part I. latifrons species-group

The latifrons species-group (=Brachycallimerus sensu Chapin 1924, Corporaal 1950; = flavofasciatus-group sensu Kolibáč 1998) of Callimerus Gorham is redefined and revised. Five species are recognized including one new species Callimerus cacuminis Yang & Yang sp. n. (type locality: Yunnan, China). Callimerus flavofasciatus Schenkling, 1902 is newly synonymized with Callimerus latifrons Gorham, 1876. Callimerus trifasciatus Schenkling, 1899a is transferred to the genus Corynommadius Schenkling, 1899a. Callimerus gorhami Corporaal, 1949 and Callimerus pallidus Gorham, 1892 are excluded from the latifrons species-group (their assignment to a species-group will be dealt with in a subsequent paper). A key to species of the latifrons species-group is given and habitus of each type specimen, male terminalia, and other diagnostic characters are illustrated.     

The genus Gymnetron from China with description of pre-imaginal stages of G. miyoshii,G. auliense and G. vittipenne (Coleoptera,Curculionidae)

There are four species of Gymnetron in China recorded to date including Gymnetron miyoshii Miyoshi, 1922, Gymnetron villosipenne Roelofs, 1875, Gymnetron auliense Reitter, 1907 and Gymnetron vittipenne Marseul, 1876, of which the last two are new country records. The pre-imaginal stages including eggs, mature larvae and pupae of Gymnetron miyoshii, Gymnetron auliense and Gymnetron vittipenne are described and illustrated. In addition, their diagnostic characters (larvae and pupae) are discussed and differentiated, and notes on some of their biological parameters are provided. Potential ecological impacts between Gymnetron weevils and their host Veronica spp. also are provided.