Changes in the karyotype of the cell line,DSIR-HA-1179, and a comparison with that of its parent insect,Heteronychus arator (F.) (Coleoptera: Scarabaeidae)

Abstract

Eighteen months after establishment of the primary cell culture, 36 metaphase nuclei of cell line DSIR-HA-1179, derived from the black beetle, Heteronychus arator (F.), had between 32 and 43 chromosomes; one cell contained 67 chromosomes. Structural abnormalities such as double minute chromosomes, ring and di- and tri-centric chromosomes were observed. Thirty-six months after establishment the chromosomes appeared to be similar, but the number of chromosomes per cell was much more variable (range, 12–73; 42 metaphase cells). The modal chromosome number of testicular tissues from H. arator was 2n = 20 — including an Xy pair — which is characteristic of the Scarabaeidae. The karyotype of DSIR-HA-1179 cells is unstable, with the number of chromosomes becoming more variable with continued propagation.     

Anatomy and histology of the alimentary canal of the black beetle,Heteronychus arator

Abstract

The gut anatomy of adult and third- instar larval black beetle is described, illustrated, and discussed in relation to the condition reported for other scarabs.     

Late immature mortality is the major influence on reproductive success of African black beetle, Heteronychus arator (Fabricius) (Coleoptera: Scarabaeidae), in a Mediterranean-climate region of Australia

In field and laboratory studies, mortality of African black beetle, Heteronychus arator, in the winter-rainfall, Mediterranean-type climate region of south-western Australia was higher in the late immature stages during summer than in the early immature stages that occur during spring, a contrast to summer-rainfall climatic regions. Greatest mortality occurred around the pupal stage in contrasting soil types, despite drying differences in summer and supplementary watering in some plots. Sampling of natural populations confirmed experimental results that mortality in late immature stages is the major factor limiting H. arator populations under a Mediterranean-type climate. Inter-generation increase in H. arator abundance was uncommon, explaining the consistent abundance typically observed between years in south-western Australia. Random dispersal of newly emerged adults in autumn was inferred to restore uniformity in adult abundance between areas of varying favourability for immature survival.     

Mobilization of soil phosphorus during passage through the gut of larvae of Pachnoda ephippiata (Coleoptera: Scarabaeidae)

Soil macrofauna play important roles in the mobilization of soil nutrients. The influence of gut passage on soil phosphorus availability was investigated using the larvae of the scarabaeid beetle Pachnoda ephippiata. Gut passage significantly increased the levels of available P in the feces over that of the soil consumed. ³¹P-NMR recorded the changes in the nature of organic P in alkaline extracts from gut content. Alkaline phosphatase activity was high in the alkaline midgut, but low in the hindgut and soil. Ferric iron (Fe³⁺) in the soil was reduced to ferrous iron (Fe²⁺) in the gut. The amount of Ca²⁺ was lower in the gut than in the soil. Iron reduction and the decrease of Ca²⁺ concentration in the gut would reduce P sorption. We think that the following effects are responsible for increased availability of P during the gut passage: alkaline extraction of soil organic matter; hydrolysis of organic phosphate esters with alkaline phosphatase; digestion by the resident microorganisms; and changes in the concentration of metal ions during gut passage. This study suggests that the feeding activities of humivorous larvae would affect the amount of soil P available to plant growth.     

The biology and life history of currant clearwing,Synanthedon tipuliformis (Lepidoptera: Sesiidae), in Canterbury

Abstract

Details of the life cycle and biology of currant clearwing, Synanthedon tipuliformis (Clerck), in Canterbury, New Zealand, are discussed. The adults live for about 7 days, and are found from mid November to early January. The sex ratio approximates 1:1. Adults are active only when the air temperature exceeds 15°c, and peak flight activity is observed on cloudy days at 20-23°c. Males are attracted to females between 1400 h and 1600 h, and mating lasts for over 2 h. Fecundity averaged about 100 eggs per female, and fertility exceeded 98%. Egg incubation required an average of 19 days in the field; the thermal constant is 91 day degrees. The mean number of eggs per blackcurrant cane varied in different years from 2.68 to 13.54; there was no significant difference between blackcurrant varieties in the same year. Larvae entered the cane through openings or axillary buds and then fed on the pith until late April or May. Quiescence occurred during winter, and feeding resumed in late August or September. Larvae tunnelled 15.20 ± 0.74 cm of pith. It is suggested that there are six larval instars. Mean numbers of larvae per cane varied in the early stage from 1.91 to 7.36, and at the post-winter stage from 1.23 to 3.10. Pupation occurred in mid October, and the pupal stage lasted for up to 6 weeks; the thermal constant is 216 day degrees. Mortality factors discussed include establishment failure, parasites, pathogens, predators, larval combat, winter pruning, loss of pupae at cane breaks, and pupal eclosion failure. The first record of the fungus Cordyceps sp. attacking currant clearwing is reported.     

Effect of root extracts of resistant pasture plants on the feeding and survival of black beetle larvae,Heteronychus arator (Scarabaeidae)

Abstract

Crude root extracts of the black beetle-resistant legumes red clover, white clover, lupin, Lotus pedunculatus, and lucerne significantly reduced feeding by 3rd-instar black beetle larvae when incorporated in an artificial medium containing a strong feeding stimulant. The same extracts were toxic when administered orally. Lucerne and L. pedunculatus contain particularly active feeding deterrents and toxins. The root of the black beetle-resistant grass Phalaris aquatica (= P. tuberosa), like that of the susceptible perennial ryegrass, had no effect on larval feeding or survival. Lotus pedunculatus was very much more active against black beetle larvae than L. corniculatus or L. corniculatus × pedunculatus.     

The male reproductive system of Costelytra zealandica (White)(Coleoptera: Scarabaeidae: Melolonthinae)

Abstract

The morphology and histology of the male internal reproductive organs of Costelytra zealandica show many similarities to other Scarabaeoidae, and are particularly close to other Melolonthinae and to Rutelinae. Testes follicles of C. zealandica have the usual structure for Melolonthinae with basal lobes surrounding the ends of the vasa efferentia. Epithelial cells of the vasa efferentia, vasa deferentia, and vesiculae seminales have similar densely basophilic cytoplasm but muscle layers are best developed around the latter. Accessory glands lack muscle and are not differentiated histologically into regions but do differ from their reservoirs. The ejaculatory duct has a cuticular intima and is differentiated into anterior and posterior regions. Both are surrounded by a muscular sheath which expands in the posterior region to enclose fluid. This forms a hydraulic mechanism for everting the internal sac during intromission. The parameres hook into the female’s genital chamber during copulation and have no pincer action. Probable homologies are listed between muscles of the external genitalia and anus of C. zealandica and other Scarabaeoidea.     

Nesting of Afrotropical Oniticellus (Coleoptera, Scarabaeidae) and its evolutionary trend from soil to dung

Abstract. 1. Oniticellus egregius Klug constructs brood ovoids of dung in the soil immediately under the edge of animal droppings. Each successive brood ovoid is enveloped within a soil shell. After completion of brood construction, loose earth is cleared from around the broods to produce a brood chamber. The immatures are then abandoned as eggs or first instar larvae.
2. O.planatus Castelnau and O.formosus Chevrolat usually construct brood balls of dung within animal droppings. Each brood is progressively enlarged by the addition of further dung after egg-laying. This enlargement is slight in O.planatus and marked in O.formosus. Parental females of both species remain in the brood chambers during development of the immatures which are abandoned principally as pupae.
3. Under very moist experimental conditions, O.planatus buries dung and constructs broods shallowly in the soil. Such nests are frequently connected to the pad by a short tunnel.
4. From a consideration of behavioural patterns it is suggested that the specialized nesting habits of these species have been derived from those of dung-burying ancestors similar to the modern genus, Euoniticellus, through reduction and loss of tunnelling in the soil.     

中国四种蜣螂幼虫形态记述(鞘翅目:金龟科:金龟亚科)

基于3龄幼虫首次描述了中国4种蜣螂幼虫的形态特征,分别是：捷氏凯蜣螂Caccobius jessoensis Harold、短亮凯蜣螂C．brevis Waterhouse、双顶嗡蜣螂Onthophagus bivertex Heyden和小驼嗡蜣螂0．gibbulus（Pallas）。文中列出了中国凯蜣螂和嗡蜣螂属幼虫分种检索表。标本保存在沈阳农业大学昆虫博物馆。     

Effect of agronomic factors on the spatial distribution of greyback canegrub, Dermolepida albohirtum (Waterhouse) (Coleoptera: Scarabaeidae), in sugarcane in the Burdekin River Irrigation Area

Abstract A series of studies were undertaken examining the factors that impact on the spatial distribution of greyback canegrub infestations in sugarcane in the Burdekin region of Queensland. Historic records of damage by greyback canegrub showed that sugarcane blocks planted or harvested earlier than surrounding blocks were more likely to be damaged than blocks planted or harvested later. The derived hypothesis that sugarcane height may be the primary determinant of where damage occurs was confirmed in field studies. The tallest sugarcane blocks at the time of oviposition consistently had the highest grub populations. There was no difference in the distribution of damage between the cultivars Q96 and Q117 and the age of these crops also had no impact. The finding that sugarcane height is the primary determinant of where damage occurs on Burdekin farms opens the possibility of using it as a tool to manipulate where canegrubs oviposit and the development of a range of associated cultural control strategies.     

Site‐specific profiles of biochemical properties in the larval digestive tract of Japanese rhinoceros beetle,Trypoxylus dichotomus (Coleoptera: Scarabaeidae)

The larvae of Japanese rhinoceros beetle, Trypoxylus dichotomus, feed on dead plant material in forest soils that are derived from fallen leaves broken down by basidiomycete fungi. Our previous work provided an understanding of the degradation of polysaccharides in dead plant material by T. dichotomus larvae and reported the complexity of the physicochemical and biochemical environment of the larval gut. Here, we examined ten divisions of the digestive tract of T. dichotomus larvae for physicochemical and biochemical conditions to elucidate site‐specifically functional properties along the tract. The distribution of potassium ions, pH, and acetic acid differed markedly along the length of the digestive tract with the potassium ion concentration profile closely reflecting that of pH along the length of the digestive tract. Distinct physicochemical environments were maintained in the digestive tract along with site‐specific polysaccharide degradation. Based on these findings, we suggest that there are metabolic relationships between the activities of the enzymes involved in polysaccharide degradation, the presence of intermediate metabolites and location along the digestive tract. Furthermore, we revealed that the anterior region of the gut plays an important role in the degradation of polysaccharides in the digestive tract of T. dichotomus larvae.     

The evolution of parental behaviour in Scarabaeinae (Coleoptera, Scarabaeidae): an experimental approach

ABSTRACT.

• 1 Dung beetle lifestyles are reviewed. Most Scarabaeinae lay their eggs in dung masses that are packed into underground chambers, but Coprini and Scarabaeini typically lay their eggs in free-standing brood balls and it is in these tribes that parental care of the brood has evolved.
• 2 Brood balls are constructed by aggregating fragments of dung. This technique is derived from the method of gathering dung at the surface. Larvae developing in brood balls are better protected against dehydration and parasite attack. The repair technique of Scarabaeine larvae preadapts them to life in brood balls.
• 3 Parental care by Copris lunaris depends on appropriate responses by the female to the brood, and it has the selective advantage of protecting the brood against parasites. Preadaptations for parental care in‘non-brooding’Coprini are discussed.
• 4 Variations in the basic Copris nesting behaviour are summarized. Similar variations can occur spontaneously in C.lunaris and can also be released by unusual circumstances.
• 5 C.lunaris females could in principle cooperate but certain factors have prevented this social evolution. The significance of the transient cooperation with the male beetle is discussed.

     

Dung feeding in adult scarabaeines (tunnellers and endocoprids): even large dung beetles eat small particles

Abstract 1. The maximum size of ingested particles was determined in 15 species of adult dung beetle (Scarabaeidae: Scarabaeinae) by mixing small latex or glass balls of known diameter into the dung used as food. Twelve species (tribes Coprini, Onitini, Oniticellini, and Onthophagini) were tunnellers (making dung stores for feeding and breeding in the soil below the pat) and three species (tribe Oniticellini) were endocoprids (feeding and breeding in the dung pat itself).
2. The test species, covering a wide range of body size (fresh weights 0.05–7.4 g), ingested minute particles only (maximum diameter 8–50 µm), and there was a statistically significant but numerically small increase in particle size with body weight.
3. When the effect of body size was taken into account, taxon (tribe), ecological group (tunneller/endocoprid), and dung preference (coarse/fine) had no significant effect on the size of ingested particles.
4. Tests using two tunnelling species did not indicate that beetles use their mandibles to grind dung particles prior to ingestion.
5. The results suggest essentially the same feeding mechanism in all adult tunnelling or endocoprid scarabaeines that eat fresh dung. Larger, indigestible plant fragments are avoided by filtration, and ingestion is confined to very small particles of higher nutritional value.     

Phylogeography of the Namib Desert dung beetles Scarabaeus (Pachysoma) MacLeay (Coleoptera: Scarabaeidae)

Aim Namib biogeography in many instances remains reliant on advanced and detailed systematic studies. This study attempts to combine molecular phylogenetic data, geology and palaeo‐climatic data to (i) resolve the relationships of the 13 morphological species of Scarabaeus (Pachysoma) and (ii) relate their evolution to past climatic and geological events. Location South Africa and Namibia. Methods Sequencing of a 1197 bp segment of the mitochondrial cytochrome oxidase I (COI) gene of the 13 species within Scarabaeus (Pachysoma) was undertaken. Analyses performed included Parsimony and Maximum Likelihood as well as imposing a molecular clock. Results The molecular phylogeny showed strong support for 11 of the 13 morphological species. The remaining two species, S. (P.) glentoni and S. (P.) hippocrates, formed a complex and could not be assigned specific status on the basis of the COI gene phylogeny. Strong support for the three species formerly classified within the genus Neopachysoma was consistently obtained. The subgenus appears to have arisen c. 2.9 Ma. Species within the subgenus arose at different times, with the common ancestor to Neopachysoma and the hippocrates complex having evolved 2.65 and 2.4 Ma, respectively. Scarabaeus (P.) denticollis, S. (P.) rotundigenus, S. (P.) rodriguesi and S. (P.) schinzi are some of the youngest species, having diverged between 2 million and 600,000 years ago. Main conclusions Scarabaeus (Pachysoma) is a derived monophyletic clade within the Scarabaeini. The subgenus appears to be young in comparison with the age of the Namib Desert, which dates back to the Miocene (c. 15 Ma). The psammophilous taxa are shown to disperse with their substratum and habitat, barchan dunes. Clear south/north evolutionary gradients can be seen within the species of this subgenus, which are consistent with the unidirectional wind regime. Species with a suite of mostly plesiomorphic characters have a southerly distribution while their derived psammophilous relatives have central to northern Namib distributions. Major rivers such as the Orange, Buffels and Holgat appear to be gene barriers to certain species as well as areas of origin of speciation events.     

Brood ball construction by the non-brooding Coprini Sulcophanaeus carnifex and Dichotomius torulosus (Coleoptera, Scarabaeidae)

ABSTRACT.

• 1 Feeding burrows made by S.carnifex and D.torulosus adults consisted of tunnels filled with sausage-shaped masses of dung. Brood balls were made by taking fragments of dung from an adjacent feeding burrow and aggregating them into a small sphere which was gradually enlarged and then coated with soil.
• 2 S.carnifex adult females showed no response to their own eggs (unlike Copris lunaris: Klemperer, H.G. (1982) Ecological Erltonzology, 7, 155–167). S.carnifex larvae made and maintained an air channel to the upper pole of the ball and they are in this respect preadapted to receive parental care.
• 3 Compared with a brood mass, a brood ball was less likely to be attacked by Meptoparasitic larvae. The soil coat retarded drying of the brood ball by increasing the total mass of moisturecontaining material.

     

Normal and atypical nesting behaviour of Copris lunaris (L.): comparison with related species (Coleoptera, Scarabaeidae)

Abstract. 1. The lifecycle, mating and larval behaviour of Clunaris are described. Adults appeared in the autumn and nested in the following spring. The female beetle remained in the nest with the brood and could nest again the following year.
2. Nesting was initiated when virgin females were mated in the spring. Brood balls were formed by techniques sirnilar to those used by Scarabaeini. The female beetle left the nest soon after the first imagos broke out of the brood balls.
3. Nesting behaviour was readily modified by external conditions. Many parts of the sequence could be repeated or omitted. The female beetle left the nest if the brood was removed, but she remained for longer than usual if younger brood was substituted near the end of the normal nesting period.
4. Certain experimental conditions released behaviour patterns typical of other species. These were formation of superficial nests or of two-chambered nests, oviposition before completing the brood ball, and coating of the brood balls with soil (all found in other Coprina), as well as ball rolling and ball burial (found in Scarabaeini). The results are discussed in relation to the evolution of Copris nesting behaviour.