Phylogeography of the scarab beetle Antitrogus parvulus Britton (Coleoptera: Scarabaeidae) in south-eastern Queensland, Australia

Abstract  This study surveys the population genetic structure of Childers canegrub, Antitrogus parvulus , to elucidate its population dynamics and gene flow. Antitrogus parvulus is a pest of sugarcane in the Bundaberg region and this knowledge can be used to optimise integrated pest management practices. Here, base-pair differences in the cytochrome oxidase II gene ( COII ) were used to characterise haplotypic diversity, infer levels of gene flow, and phylogenetic relationships of alleles and their phylogeographical structure. There were 28 unique haplotypes among the 70 sequenced individuals from the seven locations. All three variance components (among regions, among populations, within populations) are highly significant, with highest genetic diversity among regions and lowest among populations within regions. A positive correlation between migration rates and geographical distance and significant phylogeographical structure between four main geographical regions. The main implication of these findings for pest management is that if a grower can eliminate an existing infestation within a field, then reinvasion will be slow and further outbreaks within that field are unlikely to occur. The low dispersal ability of females also means that any resistance to insecticides that develops is likely to remain localised, but will rapidly become dominant within the affected population.     

Immature stages of the bee fly Ligyra satyrus (F.) (Diptera: Bombyliidae): A hyperparasitoid of canegrubs (Coleoptera: Scarabaeidae)

We describe the third- and fourth-instar larva, pupa and biology of the hyperparasitoid bee fly Ligyra satyrus (Fabricius). The larval and pupal morphology of the bee fly is typical for members of the subfamily Anthracinae. The bee fly larvae are found inside cocoons of the scoliid Campsomeris tasmaniensis Saussure, an external parasite of canegrubs (Coleoptera: Scarabaeidae) in sugarcane fields at Ayr and Bundaberg, Queensland. Ligyra satyrus has been recorded attacking only C. tasmaniensis . Ligyra and its relatives are all parasites of predatory and parasitic, ground-nesting aculeate Hymenoptera such as Sphecidae, Pompilidae, Tiphiidae and Scoliidae. Larval morphology of the hyperparasite is similar to other ectoparasitic Bombyliidae and pupal morphology is compared to that of species in the same and related subfamilies. Rates of hyperparasitism at Gordonvale reported in the early 1900s are relatively high, but our results show that currently they are very low at Ayr and Bundaberg. These results suggest that the impact of the bee fly on natural control of the canegrubs by scoliids varies considerably.     

A new Oxyurida (Thelastomatidae) from Cyclocephala signaticollis Burmeister (Coleoptera: Scarabaeidae) from Argentina

Cephalobellus cyclocephalae n. sp. (Oxyurida: Thelastomatidae), a parasite of larvae of Cyclocephala signaticollis (Coleoptera, Scarabaeidae), found in Argentina is described and illustrated. It is characterized by the cuticle striated at the anterior end in both sexes, with 15 annules, buccal cavity short and not armed, and the male with 4 pairs of genital papillae, 1 pair of preanal papillae, 3 pairs of postanal papillae.     

Effect of Soil Moisture on Oviposition by Childers Canegrub, Antitrogus parvulus Britton (Coleoptera: Scarabaeidae)

Ovipositing Childers beetles, Antitrogus parvulus Britton, exhibit preference for soils of certain moisture levels. In a choice trial, A. parvulus laid most eggs in soil at approximately—74 kPa (near field capacity), no or very few eggs in soil near wilting point or drier, and few eggs in soil above field capacity (approximately -5.7 kPa). Under no-choice conditions most females retained their eggs if soil was near wilting point, oviposited immediately in soil near field capacity, and tended to extend egg-laying in soil above field capacity. Females in very wet soil laid many eggs when soil was changed to near field capacity within 3 d. After 3 d there was very little egglaying response to a change to soil near field capacity.     

Pathogenicity of Heterorhabditis bacteriophora, Steinernema glaseri, and S. scarabaei (Rhabditida: Heterorhabditidae, Steinernematidae) Against 12 White Grub Species (Coleoptera: Scarabaeidae)

We compared the pathogenicity of the entomopathogenic nematodes Heterorhabditis bacteriophora, Steinernema glaseri, and S. scarabaei against third instars of 12 white grub species. The Japanese beetle (Popillia japonica) was highly susceptible to all nematode species. Oriental beetle [Exomala (=Anomala) orientalis], European chafer (Rhizotrogus majalis), Asiatic garden beetle (Maladera castanea), and the May/June beetles Phyllophaga crinita, Ph. congrua, and Ph. (Subgenus Phytalus) georgiana were highly susceptible to S. scarabaei but had mediocre to low susceptibility to H. bacteriophora and S. glaseri. The black turfgrass ataenius (Ataenius spretulus) was very susceptible to H. bacteriophora but had mediocre susceptibility to S. glaseri and S. scarabaei. Northern (Cyclocephala borealis) and southern masked chafer (C. lurida) had mediocre and southwestern masked chafer (C. pasadenae) and green June beetle (Cotinis nitida) had low susceptibility to all nematode species.     

Morphology and Distribution of Sensilla on the Antennae of Hylamorpha elegans Burmeister (Coleoptera: Scarabaeidae)

Considering that sensilla constitute important functional elements of sensory systems in insects, the aim of this study was to determine the type and distribution of sensilla in the antennae of Hylamorpha elegans Burmeister examined by scanning electron microscopy. Hylamorpha elegans antennae are lamellate and consist of the scape, pedicel, and flagellum. The antennal club of this beetle consists of three terminal plates: proximal, middle, and distal lamellae. Four types of sensilla were observed in the lamellae from both sexes: sensilla trichoidea, chaetica, coeloconica, and placodea. Antennal length was larger in males than in females, and significant sexual variation in the number of sensilla placodea and sensilla coeloconica was observed.     

Overwintering,soil distribution and phenology of Childers canegrub,Antitrogus parvulus (Coleoptera: Scarabaeidae) in Queensland sugarcane

In this study, the question of whether Childers canegrub, Antitrogus parvulus (Britton) overwinters in the subsoil was addressed. Irrigated fields of sugarcane were sampled during a 2-year period near Bundaberg in southern Queensland. Antitrogus parvulus overwintered as second and third instars at each of three sites. During autumn and winter third instars of different allochronic (separated in age by 12 months) populations occurred together and could not be readily separated. Field-collected third instars were reared on ryegrass and separated into two age groups based on the date of pupation. Third instars in the first year of their life cycle (young third instars) remained at shallow depth (100-200 mm) and did not overwinter in the subsoil as once thought. Minimum temperatures during winter were 13-16 degrees C and did not prevent young third instars from feeding and gaining weight. Third instars in their second and final year moved downwards from late summer and pupated in the subsoil at 293-425 mm in spring. General phenology was as previously reported with first instar larvae occurring from January until April, second instars from January until November and third instar larvae throughout the year. Prepupae and pupae were found between October and December and adults occurred in soil during November and January. Batches of eggs occurred at a mean depth of 350 mm. First and second instars occurred predominantly at relatively shallow (100-200 mm) depths in the soil profile. All stages tended to be most common under rows of sugarcane rather than in the interrow.     

Revision and phylogenetic analysis of the Central American endemic genus Phalangogonia Burmeister (Coleoptera: Scarabaeidae: Rutelinae: Anoplognathini)

Abstract.  Phalangogonia Burmeister is revised and now includes eight species: P . dispar Ohaus, P . jamesonae , sp.n., P . lacordairei Bates, P . obesa Burmeister, P . parilis Bates, P . punctata Franz, P . ratcliffei , sp.n. and P . sperata Sharp. Phalangogonia debilidens Ohaus is placed in synonymy with P . sperata . Lectotypes are designated for the following nominal species: P . dispar Ohaus, P . lacordairei Bates, P . parilis Bates and P . championi Bates. Neotypes are designated for: P . obesa Burmeister, P . sperata Sharp, P . stipes Sharp and P . debilidens Ohaus. A cladistic analysis of the species of Phalangogonia was executed using thirty-two morphological characters of adults.     

A revision of the genus Paronthobium from New Caledonia (Coleoptera: Scarabaeidae: Scarabaeinae: Epilissini)

A revision of the New Caledonian genus Paronthobium Paulian 1984 is presented. Anonthobium Paulian 1984 is synonymized with Paronthobium Paulian 1984 after evaluating the diagnostic characters originally introduced by Paulian to separate them. Upon examination of the type specimens, Onthobium caledonicum Paulian 1935 is separated from O. simplex Fauvel 1903 and restored as valid. Anonthobium moui Paulian 1984 is synonymized with Anonthobium micros Paulian 1984. Fifteen new species are described: P. adio n. sp., P. daghfousi n. sp., P. dierkensi n. sp., P. farino n. sp., P. iac n. sp., P. julieni n. sp., P. memaoya n. sp., P. minutum n. sp., P. nasutum n. sp., P. orientale n. sp., P. peckorum n. sp., P. petchecara n. sp., P. subdentatum n. sp., P. taom n. sp. and P. tchingou n. sp. The genus Paronthobium is now composed of 22 species. Illustrations of parameres and of male protibiae are provided for each species. Distribution maps and a key to species are given.     

Rearing Costelytra zealandica (Coleoptera: Scarabaeidae)

Interaction between larvae can be a cause of mortality when scarabaeid larvae are concentrated in a confined volume of soil. Larvae of Costelytra zealandica (White), the New Zealand grass grub, were held for 30 days at population densities between 1 and 50 larvae per 200 ml of medium, and the effect of crowding on their survival and weight change was assessed. Larval density had no effect on survival in soil plus chopped sheep dung (3 :1), with up to 10 2nd‐instar larvae or 5 3rd‐instar larvae per 200 ml of medium. Larval survival and weight gain were increased by adding germinating ryegrass seed (Grasslands Ruanui) to the medium base, but the effect of density did not diminish. Weight gain of 3rd‐instar larvae decreased as their density increased. When the amount of germinating ryegrass seed in the medium was varied, there was no significant difference between the survival of larvae held in treatments with 5, 25, and 50 g of seed per litre of medium. Survival was significantly lower with 0 and 100 g of seed per litre of medium. It is concluded that, in rearing conditions, the final density of fully grown 3rd‐instar larvae should be a maximum of about 20 per litre of medium to prevent mortality caused by larval interaction—provided that adequate food is available.     

Antenna morphology and sensilla microstructure of the male and female scarab beetle,Lepidiota mansueta Burmeister (Coleoptera: Scarabaeidae)

Studies on Lepidiota mansueta Burmeister were conducted to describe and compare the external morphology of the antenna and its sensilla of male and females. Distinct variations were observed in antennal segments between the sexes with males possessing longer scape, pedicel, flagellum and lamellar club segments. Variation was also seen in the antennal sensilla, with males possessing three different types of sensilla while the females possessed seven types of sensilla. Sensilla trichodea (TRS), sensilla placodea (PLAS) type I and sensilla placodea (PLAS) type II were common in both sexes while sensilla chaetica (CHS), sensilla auricilica (AUS) type I, sensilla auricilica (AUS) type II and sensilla auricilica (AUS) type III were found only in females.     

Synopsis of the Argentinian scarab genus Pseudogeniates Ohaus (Coleoptera,Scarabaeidae, Rutelinae)

The scarab beetle genus Pseudogeniates Ohaus (Scarabaeidae: Rutelinae: Rutelini) is endemic to Argentina. The genus includes three species: Pseudogeniates cordobaensis Soula, Pseudogeniates intermedius Ohaus, and Pseudogeniates richterianus Ohaus. We characterize the genus, provide a key to species, redescribe and diagnose each species, provide spatial and temporal distributions, and discuss distributions of the species in relation to eco-regions and areas of endemism in Argentina.