Dung burial strategies in some South African coprine and onitine dung beetles (Scarabaeidae: Scarabaeinae)

ABSTRACT.

• 1 The dung colonization and dung burial behaviour of twelve crepuscular/nocturnal tunnelling (paracoprid) species of beetles were examined in order to identify mechanisms which might facilitate resource (dung) partitioning. The species were selected from a diverse assemblage of dung beetles, the members of which coexist in the sandy-soil regions of Natal, South Africa.
• 2 The pattern of dung colonization in relation to dung age was examined in the field using baited pitfall traps. Some species, e.g. Onitis deceptor Peringuey, Catharsius tricornutus De Geer and Copris elphenor Klug, showed a marked preference for fresh dung (1–2 days old) whereas other species, e.g. O. viridulus Boheman and Copris fallaciosus Gillet, preferred older dung (3–7 days old).
• 3 Two distinct patterns of dung burial were recognized. In the Coprini, dung burial was complete within 24–48h of pad colonization, and the level of dung burial was similar in the laboratory and in the field. In the Onitini, dung burial occurred progressively over a 12-day period, although the timing of initiation of dung burial varied between species: in O. deceptor nearly all individuals had begun burial within 2 days of pad colonization, whereas only 20% of O. viridulus had commenced dung burial by that time. However, nearly all O. viridulus had buried substantial quantities of dung by day 12.
• 4 The mass of dung buried per pair by the larger coprine beetles (100–300 g) and onitine beetles (400–1000 g) suggests that there is potential for inter- and intraspecific competition, even in pads colonized by relatively few beetles. The colonization and use of dung of different ages are discussed as means of resource partitioning in relation to the relative abilities of species to compete for dung.

     

The daily onset of flight in the crepuscular dung beetle Onitis alexis

The role of light intensity and temperature in determining the onset of flight in the crepuscular dung beetle Onitis alexis Klug (Coleoptera: Scarabaeidae) was examined. Flight under natural light was highly synchronized, with two-thirds of the beetles that flew flying over a period of 10–12 min. In six flights on different days, the mean time of onset varied by up to 13 min, but mean onset occurred at fixed light intensity. Absolute light intensity therefore appears to be a vital cue in determining flight onset. Mean onset remained at this intensity when dusk was advanced artificially by up to about 8 min. However, when dusk was brought further forward, mean flight occurred at lower intensities and onset of flight took place over a longer period. This is interpreted as an overlapping of the period of light intensities suitable for flight with the circadian rhythm that brings the beetles to the surface. No beetles flew when kept under constant bright light or in the dark during the dusk period. Under conditions of constant dusk, the beetles appeared uncoordinated and, although the median time of onset of flight was only 3 min later than in the control flight, onset of flight was spread out over a much longer period. At soil temperatures of 20–22 °C, over 90% of the beetles flew. This percentage decreased with decreasing temperature, and less than 10% flew at temperatures of 16–17 °C.

---

L'incitation quotidienne au vol chez e bousier crépusculaire Onitis alexis Klug (Col. Scarabaeidae)

Résumé L'examen a porté sur le rôle de l'intensité lumineuse et de la température sur l'incitation au vol chez Onitis alexis. Le vol en lumière naturelle est fortement synchronisé, avec les deux tiers des adultes qui s'envolent en 10–12 min. Sur six vols pour différents jours, le moment moyen d'envol variait de 13 min, mais l'envol moyen avait lieu à une intensité lumineuse déterminée. La valeur absolue de l'intensité lumineuse paraît ainsi un signal crucial dans la détermination et l'incitation au vol. Le moment d'envol se maintient à cette intensité quand le crépuscule est artificiellement avancé jusqu'à 8 min environ. Cependant, quand le crépuscule est rendu encore plus précoce, l'envol moyen se produit à des intensités plus basses et est étalé. Ceci peut être interprété comme un chevauchement de la période des intensités lumineuses favorables à l'envol avec le rythme circadien qui conduit les bousiers à la surface. Aucun adulte ne vole quand il y a maintien de lumière constante ou d'obscurité à l'heure du crépuscule. En présence de crépuscule constant, les réponses sont hétérogènes, et, bien que le moment médian d'envol ne soit retardé que de 3 min, par rapport aux témoins, l'incitation à l'envol est étalée sur une période plus longue. Avec des températures au sol de 20–22 °C, plus de 90% des adultes s'envolent. Le pourcentage diminue avec la température, et moins de 10% s'envolent à 16–17 °C.

     

Superposition optics and the time of flight in onitine dung beetles

Dung beetles fly to fresh dung, with vision essential for flight navigation. The daily period of flight varies among different species: some beetles fly only in sunlight, others only when ambient light levels change rapidly during dusk or dawn and others in the constant dark of night. Measurements of the optical properties of the lenses, eye geometry and photoreceptor dimensions were used in a computer ray-tracing model to determine the optical performance of the superposition eyes of nine species of onitine dung beetles. Eye sensitivity to light is determined mainly by body size, by the refractive-index parameters and size of the crystalline cones, and by the photoreceptor dimensions. Based on the optics of the ommatidial lenses and absorption of light in the retina, the most sensitive eyes, found in the crepuscular-nocturnal beetles, are 85 times or nearly two log units more sensitive than the eyes of the diurnal beetles. Three possible criteria are considered to determine the best position for the retina: maximum amount of light absorbed in the target rhabdom; maximum amount of light falling on the target rhabdom (best focus); and maximum resolution. The structure and physiological optics of the superposition compound eyes of an onitine dung beetle are matched to the range of light intensities at which it flies. Accepted: 4 February 1998     

The phenology of Onitis alexis (Coleoptera: Scarabaeidae) in the Araluen Valley: Survival in a marginal environment

The introduced African dung beetle, Onitis alexis Klug, has become established in the warmer regions of Australia. The south-eastern limit of its current distribution is Moruya, NSW, and the Araluen Valley 50 km inland. At Araluen newly emerged beetles are present in dung in late spring, summer and autumn. Egg-laying starts 1-2 weeks after emergence and continues throughout the summer and autumn, as indicated by the presence of parous females in the population and of broods under experimental pads. Eggs laid in December/January produce adults in late summer and autumn, those laid from February to April produce adults in the following spring and summer. In the laboratory, mortality of larvae is high in cold (0–16°C), wet conditions and their development is delayed in warm (25°C and 27°C), dry conditions. This delay was confirmed in the field during the summer drought of 1982-83 when predicted times of emergence (based on day-degree summation in the soil) always preceded the observed emergence time of the local population, as well as preceding the emergence of beetles developing from eggs laid at known times. Follicle resorption in adult females was related directly to increasing age and to rainfall. Dung collected from hayed-off pasture did not affect fecundity, but caused larval mortality. Adults survived the winters at Araluen in some years, and immatures survived best during dry winters, being facilitated in this by a cold-induced larval diapause. Onitis alexis larvae can survive wet or dry summers, and cold dry winters (down to about 0°C) but not wet winters. This seems to be the major factor limiting the southern distribution of the species.     

Distribution and fine structure of antennal olfactory sensilla in Japanese dung beetles,Geotrupes auratus Mtos. (Coleoptera : Geotrupidae) and Copris pecuarius Lew. (Coleoptera : Scarabaeidae)

The distribution and fine structure of olfactory sensilla on the antennal flagella of the Japanese dung beetles, Geotrupes auratus (Coleoptera : Geotrupidae) and Copris pecuarius (Coleoptera : Scarabaeidae) were studied by scanning and transmission electron microscopy. In both types of dung beetles, sensilla on the antennal segments were most abundant on the apical 3 lamellar segments, where sensilla basiconica were particularly concentrated. The sensilla were solely concentrated in the central part of the distal side of both the 9th and 10th segments in G. auratus and the 7th and 8th segments in C. pecuarius, respectively. The numbers of sensilla in these areas (channels) of the 9th and 10th segments in G. auratus were approximately 4,500 and 3,000, respectively. In C. pecuarius, there were about 1,900 sensilla on the 7th segment and l,700 sensilla on the 8th. The cuticles of the sensilla in both species were perforated by numerous elongate pores, with a pore density of about 45/ μm² in G. auratus and 30/ μm² in C. pecuarius. Each sensillum basiconicum in C. pecuarius was generally associated with 2 sensory neurons. The sensory cilia passed into the sensillum lumen and branched profusely, occupying most of its space. On the basis of the fine structure and dense location, these sensilla are considered to have an olfactory function for food detection.     

Crepuscular activity of adult Sericesthis geminata (Coleoptera: Scarabaeidae): Influence of circadian rhythmicity and light intensity

Subterranean Sericesthis geminata (Boisduval) beetles emerge from the soil daily during the flight season. Emergence and flight are initiated within 15 min after sunset. The beetles are active above the soil surface as the intensity of illumination decreases from 240 lux to 0.7 lux.

If young adult beetles still in their pupal cells in the soil are placed under constant, low‐intensity illumination, they first emerge at any time of day, showing no cyclical diurnal activity pattern. When such beetles are exposed to diurnal fluctuations in illuminance, the first emergence and flight occur at dusk. These beetles subsequently show a diurnal rhythm in their activity, even when exposed to constant environmental conditions. This endogenous activity cycle has a period of about 22 h, and is synchronised with diurnal fluctuations in light intensity. It is reset in response to a change in the photoperiod.

The data suggest that, after initial emergence from the soil, daily crepuscular activity is initiated by an endogenously controlled activity rhythm which causes the beetles to burrow to the soil surface shortly before dusk. At the soil surface they are exposed to fluctuations in the duration and intensity of illumination which may reset the endogenous rhythm, affecting the time of subsequent emergence.     

Attractiveness of dung beetles (Coleoptera: Scarabaeinae) to faeces from native mammals in different trophic guilds

Dung beetles are predominantly coprophagous and use mammalian faeces as their main food resource and for offspring rearing. However, these resources are generally ephemeral and scarce. The objective of this study was to verify the attractiveness to dung beetles of the faeces of nine native mammal species of the Cerrado biome in different trophic guilds. This study was conducted during the rainy season (October 2016 to March 2017) in two sensu stricto areas of the Cerrado in the Brasília National Park (PNB), Federal District, Brazil. Pitfalls containing faeces of nine mammals native to the region were used as bait (from three herbivores, three carnivores and three omnivores) for the collection of dung beetles. We collected 203 individuals and 19 species, and the most abundant species were Uroxys aff. thoracalis, Oxysternon palemo, Coprophanaeus spitzi and Diabroctis mirabilis. The most attractive faecal bait was from the omnivorous Chrysocyon brachyurus (32.67% of the individuals and 13 species). This study reveals variation in the attraction of dung beetles to native mammal dung of the Cerrado, with more abundance in the faeces of omnivores and carnivores and less in the faeces of herbivores. The species composition in the carnivore baits did not differ from that of the omnivore baits. These data indicate that changes in Scarabaeinae assemblages result from changes in mammal species such as those that have occurred in the Cerrado biome with the conversion to cattle production, which in recent years has caused intense fragmentation of habitats, expansion of agricultural and livestock activities and the introduction of exotic species. The mammal C. brachyurus, vulnerable to extinction in Brazil, should be a focus for future research, since its faeces support a great diversity of dung beetles in the Cerrado.     

Diel activity of the pink shrimp Penaeus duorarum

Twelve juvenile pink shrimp, Penaeus duorarum Burkenroad, were tested individually for 3-day periods in electronic shuttleboxes to determine their diel patterns of locomotor activity, in relation to a natural summer photoperiod. Nocturnal activity was twice that exhibited during the daytime; however, a bimodal pattern was evident with crepuscular peaks occurring at dawn and dusk. The dusk peak was more pronounced, with activity increasing markedly before sunset (indicative of an endogenous circadian rhythm component), and continuing during the initial hours of darkness, gradually declining later during the night with a secondary peak at dawn falling off to minimal activity during daylight. Crepuscular activity (mean of dawn and dusk) was twice the nocturnal average.     

Host-specificity of fiveAnacassis species [Col.: Chrysomelidae] introduced into australia for the biological control ofBaccharis halimifolia [Compositae]

Foliage-feeding beetles of the genusAnacassis [A. phaeopoda Buzzi,A. fuscata (Klug),A. fuscata var.unicolor (Burmeister),A. cribrum (Klug) andA. dubia (Boheman)] were collected fromBaccharis spp. andBaccharidastrum spp. in South America. Specificity studies showed that they were restricted to these 2 host genera. Between 1974 and 1976 these species were introduced into Australia for the control ofBaccharis halimifolia. A. phaeopoda andA. fuscata were first released in 1976. One field colony ofA. fuscata persisted for up to 3 years but no recoveries ofA. phaeopoda were made after the 1st field generation. The other species died out in quarantine and were not released.      

Host‐plant use by two Orthomeria (Phasmida: Aschiphasmatini) species feeding on Macaranga myrmecophytes

Myrmecophytes depend on symbiotic ants (plant‐ants) to defend against herbivores. Although these defensive mechanisms are highly effective, some herbivorous insects can use myrmecophytes as their host‐plants. The feeding habits of these phytophages on myrmecophytes and the impacts of the plant‐ants on their feeding behavior have been poorly studied. We examined two phasmid species, Orthomeria alexis and O. cuprinus, which are known to feed on Macaranga (Euphorbiaceae) myrmecophytes in a Bornean primary forest. Our observations revealed that: (i) each phasmid species relied on two closely‐related myrmecophytic Macaranga species for its host‐plants in spite of their normal plant‐ant symbioses; and (ii) there was little overlap between their host‐plant preferences. More O. cuprinus adults and nymphs were found on new leaves, which were attended by more plant‐ants than mature leaves, while most adults and nymphs of O. alexis tended to avoid new leaves. In a feeding choice experiment under ant‐excluded conditions, O. alexis adults chose a non‐host Macaranga myrmecophyte that was more intensively defended by plant‐ants and was more palatable than their usual host‐plants almost as frequently as their usual host‐plant, suggesting that the host‐plant range of O. alexis was restricted by the presence of plant‐ants on non‐host‐plants. Phasmid behavior that appeared to minimize plant‐ant attacks is described.     

Low local but high beta diversity of tropical forest dung beetles in Madagascar

Aims We have compared local (alpha) and regional (beta) species diversities of dung beetles in wet forests in the main tropical regions including Madagascar. Madagascar is exceptional in lacking native large herbivorous mammals which produce the key resource for dung beetles elsewhere. Location Central and South America, mainland Africa, Madagascar and Southeast Asia. Methods Trapping data on dung beetles and data on mammalian faunas were obtained from published and unpublished studies. We used our original data for Madagascar. Results Species richness of dung beetles and that of large‐bodied (> 15 mm length) species in particular were highly significantly explained by the regional number of large‐bodied (> 10 kg) mammals (R² from 50 to 80%). For a given pairwise spatial distance between two communities, beta diversity was significantly higher in Madagascar than elsewhere, explaining the very high total species richness in Madagascar in spite of low local diversity. Main conclusion The presence and numbers of large herbivorous mammals greatly influence the species richness of dung beetles in tropical wet forests. The lack of native large herbivores rather than a limited species pool explains the low local diversity in Madagascar. Exceptionally high beta diversity in Madagascar suggests a pattern of old radiation involving extensive allopatric speciation.     

Asymmetric competition in cattle dung between two species of Onthophagus dung beetle and the bush fly, Musca vetustissima

Abstract.

• 1 Competition in cattle dung pads between two dung beetles, Onthophagus ferox Harold and Onthophagus binodis Thunberg, and the bush fly, Musca vetustissima Walker, was investigated in laboratory experiments, to determine why spring fly abundance in the field did not fall following the introduction of O. binodis.
• 2 At low beetle densities, the number of eggs laid by each species was reduced by the second species. A similar amount of dung was buried by each species alone or by both together.
• 3 At high beetle densities O. binodis egg production was substantially affected by each additional O.ferox, but O.ferox egg production was not affected by each additional O.binodis. Asymmetric competition occurred because O.ferox buried more dung than O.binodis, and a greater proportion in day 1 (pre-emptive dung burial).
• 4 O.ferox caused greater M. vetustissima egg-puparia mortality than O. binodis. Mortality mostly occurred in young M. vetustissima larvae less than 1 day old. Total egg-puparia fly mortality was correlated better with the dung buried on day 1 than dung buried on day 8 (pre-emptive dung burial). O.binodis did not add to fly mortality by O.ferox at high densities because of asymmetric competition between the beetles.

     

Effects of dung beetles on seedling emergence from herbaceous seeds in the dung of sika deer (<Emphasis Type="Italic">Cervus nippon</Emphasis>) in a temperate Japanese grassland ecosystem

The effects of dung form and condition and of dung beetles on the emergence of seedlings from herbaceous seeds in sika deer dung were examined in a temperate grassland ecosystem dominated by Zoysia japonica and Hydrocotyle maritima. I conducted field experiments to compare seedling emergence between dung exposed to dung beetles and intact dung using both dung pellets and pats during a typical rainy month (June) and the hottest, drier month (August), when large numbers of seeds of the dominant species were present in the dung. The exposed dung was immediately attacked and broken up by dung beetles, whereas dung protected from the beetles remained intact. In June, at least 12 herbaceous species, including Z. japonica, H. maritima, Mazus pumilus, and Plantago asiatica, emerged from the dung, versus at least six species in August. Decomposition rates of the pellets in June and decomposition scores of the pats in June and August were positively correlated with the number of emerging seedlings, suggesting that the acceleration of decomposition by dung beetles can positively affect seed germination. In this system of interactions among sika deer, herbaceous plants, and dung beetles, sika deer dung prevented seeds from germinating, and beetles had an indirect positive effect on seedling emergence by accelerating decomposition of the dung, although the extent of the effect may depend on the dung type, plant species, and environmental factors.     

Abundance,diversity and temporal activity of adult Culicoides spp. associated with cattle in West Bengal,India

Relative abundance, species composition and temporal activity of Culicoides midges were studied for a period of 2 years (2012–2014) using suction ultra violet light traps at two sites located in the agriculture heartland of West Bengal, India. Surveillance in close proximity to cattle recorded predominance of five species with C oxystoma and C. peregrinus as the most dominant species followed by C. fulvus, C. innoxius and C. anophelis. The temporal activity of midges was investigated for seven consecutive nights at one site in August-September, 2012 and the predominant species was Culicoides oxystoma followed by Culicoides peregrinus. All of the species exhibited crepuscular activity with their flight activity increasing from dusk to dawn. Engorged adults constituted dominant age group in collections. Studies on population ecology of the adults midges are of considerable importance predicting for the epidemicity of midge-borne diseases in cattle.     

Adjustment of parental expenditure in sympatric <Emphasis Type="Italic">Onthophagus</Emphasis> beetles (Coleoptera: Scarabaeidae)

Many organisms adjust their parental expenditure to offspring in response to resource quality. However, the mechanisms underlying the adjustment in parental expenditure are not well understood. We examined the adjustments in parental expenditure and subsequent offspring performance in two sympatric, closely related dung beetles, Onthophagus ater and O. fodiens, that were provided either monkey, deer, horse, or cow dung. The egg contained within each dung brood mass provisioned by the parent beetles develops to adulthood underground. Thus, the size of the brood mass roughly represents the amount of parental expenditure. The brood mass size differed between the two species and among the four dung types. Results of offspring performance suggested that O. ater parents optimally adjusted the brood mass size in response to dung quality, whereas O. fodiens parents did not. We hypothesized that brood mass size in O. ater may increase with prolonged egg maturation caused by the lower nutrition level of cow dung. In addition, our complex results may be explained in part by the specific threshold concept of dung quality (i.e., water content and nutritional level).     

Ecosystem functioning in relation to species identity,density, and biomass in two tunneller dung beetles

1. Species abundance, biomass, and identity are the main factors that influence ecosystem functioning. Previous studies have shown that community attributes and species identity help to maintain natural ecosystem functioning. 2. This study examined how species identity, biomass, and abundance in dung pats (i.e. density) of dung beetles affect multiple ecological functions: dung removal, seed dispersal, and germination. Specifically, two species of tunnellers were targeted: Onthophagus illyricus (Scopoli, 1763) and Copris lunaris (Linnaeus, 1758). In accordance with their natural abundance, densities ranging from 10 to 80 individuals were considered for O. illyricus, and those from two to eight were considered for C. lunaris, spanning the total biomass per treatment from 0.22 to 1.76 g. 3. Results showed that, even at higher abundance, O. illyricus is not as efficient as C. lunaris. These results show that species identity, biomass, and density are crucial factors for maintaining ecosystem functioning. The combined effect of species identity and density/biomass facilitated dung removal and seed dispersal. Conversely, species identity is the only relevant factor for germination. Moreover, relationships among functions depend on the species investigated: C. lunaris showed a positive correlation between dung removal and seed dispersal, whereas O. illyricus showed a positive correlation between germination and dung removal. 4. In conclusion, optimal ecosystem functioning depends on multiple factors, such as density and species identity, and thus also on body size, nesting strategies and ecological functions investigated. Moreover, the loss of larger and efficient species cannot be compensated by higher abundances of small species.     

Patterns of alimentary resource use by dung beetles in introduced Brazilian pastures: Cattle versus sheep dung

Dung beetles (Coleoptera: Scarabaeidae) perform essential ecological functions in pastures, such as dung removal, nutrient recycling and parasite control. However, the patterns of alimentary use by dung beetles in introduced Brazilian pastures are poorly known. Here, we compared dung beetle species richness, abundance and species composition in cattle and sheep dung, and identified the dung beetle species preference by each dung type. In January 2019, dung beetles were sampled with pitfall traps baited with cattle and sheep dung in 12 introduced pastures (Urochloa spp.), in Aquidauana, Mato Grosso do Sul, Brazil. A total of 592 individuals belonging to 14 species of dung beetles were collected. Of the 14 species sampled, nine were recorded in both dung types, five were found exclusively in sheep dung and no species was exclusive to cattle dung. Species richness and abundance were higher in sheep dung. Species composition was different between the dung types. Dichotomius bos (Blanchard), Genieridium bidens (Balthasar), Onthophagus aeneus Blanchard and Trichillum externepunctatum Preudhomme de Borre were associated with sheep dung. Our results provide evidence that sheep dung is more attractive to dung beetles with a distinct community species between the two dung types, although the studied pastures have never been used before for sheep breeding. Thus, our data shows that the introduction of a new alimentary resource (e.g. sheep dung) can be an important strategy to help to obtain a more diverse dung beetle assemblage in introduced Brazilian pastures.     

The finely defined shift work schedule of dung beetles and their eye morphology

In nature, nothing is wasted, not even waste. Dung, composed of metabolic trash and leftovers of food, is a high‐quality resource and the object of fierce competition. Over 800 dung beetle species (Scarabaeinae) compete in the South African dung habitat and more than 100 species can colonize a single dung pat. To coexist in the same space, using the same food, beetles divide the day between them. However, detailed diel activity periods and associated morphological adaptations have been largely overlooked in these dung‐loving insects. To address this, we used a high‐frequency trapping design to establish the diel activity period of 44 dung beetle species in their South Africa communities. This allowed us to conclude that the dung beetles show a highly refined temporal partitioning strategy, with differences in peak of activity even within the diurnal, crepuscular, and nocturnal guilds, independent of nesting behavior and taxonomic classification. We further analyzed differences in eye and body size of our 44 model species and describe their variability in external eye morphology. In general, nocturnal species are bigger than crepuscular and diurnal species, and as expected, the absolute and relative eye size is greatest in nocturnal species, followed by crepuscular and then diurnal species. A more surprising finding was that corneal structure (smooth or facetted) is influenced by the activity period of the species, appearing flat in the nocturnal species and highly curved in the diurnal species. The role of the canthus—a cuticular structure that partially or completely divides the dung beetle eye into dorsal and ventral parts—remains a mystery, but the large number of species investigated in this study nevertheless allowed us to reject any correlation between its presence and the nesting behavior or time of activity of the beetles.     

Thermoregulation in endothermic dung beetles (Coleoptera: Scarabaeidae): effect of body size and ecophysiological constraints in flight

We explore the physiological constraints of body temperature as related to body mass and ambient temperature during flight in endothermic dung beetles showing a mass-related breakpoint where species show strong vs. weak endothermy. We found two different strategies in the dung beetles prior to flight; larger beetles (>1.9 g) elevate and maintain their body temperature (T(b)) at levels well above ambient temperature (T(a)) whereas smaller beetles' (<1.9 g) T(b) tends to conform with T(a). Physiological constraints analysis revealed a constant maximum tolerated temperature (in flight) of 42 degrees C and a minimum temperature for flight of around 25 degrees C. These, with body mass, may play a role in thermal niche partitioning and geographical distribution patterns.     

The natural history of a phoretic sphaerocerid Diptera fauna

ABSTRACT.

• 1 Three species of phoretic Sphaeroceridae kleptoparasitize the dung caches of scarab beetles in north Florida. Ceroptera sivinskii Marshall intercepts beetles under dung, then accompanies them into their burrows. Borborillus frigipennis (Spuler) rides on ball rolling and tunnelling scarabs. It perches on beetles both underground and in flight. B.singularis (Spuler) is similar in habits but is principally nocturnal.
• 2 Kleptoparasitism is probably a means of escaping environmental decay and competition in‘parent’faeces. Nonscarab competitors and predators are less abundant in beetle stored dung, and Borborillus spp. are among the few spaerocerids that flourish when large, rapidly developing calypterate flies are abundant.
• 3 Since oviposition in B.frigipennis occurs only underground, phoresy is an inexpensive and safe means to maintain contact with hosts. Males ride in order to find mates.