The Biology of a Subtropical Population of Halictus ligatus Say (Hymenoptera; Halictidae)

The ability of Manx shearwaters (Puffinus puffinus) to locate their nesting burrows at night was investigated using observation and experiments. Shearwaters walking to their burrows did so at random with respect to the wind direction, and did not vocalize, suggesting that visual cues are important to successful burrow homing. Experiments to test whether vision, audition or olfaction functioned in guiding birds back to burrows supported this conclusion.     

Activity patterns, feeding and burrowing behaviour of the crab Ucides cordatus (Ucididae) in a high intertidal mangrove forest in North Brazil

Activity patterns, feeding and burrowing behaviour of the economically important semi-terrestrial mangrove crab Ucides cordatus (Ucididae, L. 1763) was studied in a high intertidal Rhizophora mangle forest stand in Bragança, North Brazil. Video observations in the rainy and dry season were conducted over 24 h cycles at different lunar phases to investigate the behaviour of these litter-feeding crabs outside their burrows. During the rainy season, crabs stayed inside their burrows for 79% and 92% of the time during day and night, respectively. Time spent for feeding, burrowing and other activities outside their burrows was significantly longer during the day with 9.9% (night: 1.7%) and at waning and waxing moon with 9% (full and new moon: 0.9%). At neap tides (no tidal inundation) foraging and feeding activities outside burrows were clearly light-dependent, increasing at dawn and decreasing at dusk. Highest activities during daytime relate to the visual localisation of food. During the dry season, crabs spent less time inside burrows at neap tides than during the rainy season (80% and 91%, respectively). However, time spent for feeding activities was similar during both seasons. During almost all observation periods crabs collected leaf litter, but rarely fed on it outside burrows. At neap tides nearly all available litter was collected, suggesting that the U. cordatus population is litter-limited during these times. At spring tides (regular tidal inundation) the surface activity of U. cordatus was tide-dependent. Crabs closed their burrow entrances 2-3 h before flooding and re-emerged as soon as the tide retreated. During the day, burrow maintenance was the second most frequent behaviour after feeding. Agonistic interactions were regularly observed and were mainly related to burrow defence. The mean foraging radius of the crabs was only 19 cm (max: 1 m) underneath high Rhizophora mangle trees where crab densities were high. The results point to a high competition for burrows and show that U. cordatus is territorial. It is concluded that several exogenous factors, in particular light, leaf litter availability, flooding of burrows and the presence of conspecifics are important in controlling the crabs' activity patterns.     

高原鼠兔种群恢复过程中的洞穴分布动态

高原鼠兔洞穴系统的恢复是其种群恢复的关键指标之一,洞穴分布的变化可以反映种群的动态。本研究于2014-2016年在青海省祁连县对2.79 hm2高寒草甸内高原鼠兔(Ochotona curzoniae)种群密度、洞穴密度和洞穴的相对位置进行跟踪观测。其中包括6个50m×50m 的灭鼠堵洞处理、6个30m×30m 的灭鼠处理和3个50m×50m的对照处理。分别采用平均最近邻指数和平均拥挤度指数分析洞穴系统中有效洞、弃洞、粪坑和嬉戏坑的分布模式及洞系表现面积,并对各参数进行描述性和相关性分析。结果显示：高原鼠兔种群密度恢复过程中（1）有效洞的空间格局由随机向离散分布转变,弃洞由随机向聚集分布转变,粪坑和嬉戏坑无明显变化趋势;有效洞和弃洞分布格局的恢复都朝向灭鼠前状态,但恢复的都不充分;（2）有效洞最近邻指数与其自身密度正相关;弃洞最邻近指数与其自身密度负相关;粪坑、嬉戏坑最近邻指数与其自身密度无显著相关性;其中,仅粪坑的分布最近邻指数与高原鼠兔种群密度呈显著负相关;（3）有效洞与粪坑、嬉戏坑表现面积的变化情况较为一致,与弃洞呈互补态势;洞系表现面积的变异性远小于洞穴密度。结果说明：（1）高原鼠兔洞穴分布格局和洞穴密度的恢复具有滞后性;（2）有效洞、弃洞的分布格局主要受洞穴密度的影响;（3）高原鼠兔种群的恢复过程中对洞系面积的需求优先于洞口数量。     

Strategies of mate finding in the European field cricket (Gryllus campestris) at different population densities: a field study

Abstract. 1. Members of a field population of Gryllus campestris L. varied in their walking and calling activity. In both sexes, some individuals occupied burrows whereas others walked around in the observation area. Males at burrows could be either silent or calling.
2. In the course of one summer, population density decreased and the initial balanced sex ratio changed to a large surplus of males.
3. At high population density, there were equal numbers of non-calling males at burrows, calling males at burrows and walking males, while walking females predominated over females at burrows. Non-calling males at burrows achieved more encounters with females than did calling and walking males. Females met males by walking through the population and by waiting at burrows. Thus, calling and phonotaxis were not essential for mate finding and calling was less effective than previously thought.
4. At low population density calling males predominated. Calling males at burrows achieved the most encounters with females. Females met males only by walking around in the population area. Calling was thus more important in mate finding than at high population density.
5. Changes in sex ratio and population density may cause the flexibility in mate finding behaviour of individual crickets.     

Burrow structure and use in the sand fiddler crab, Uca pugilator (Bosc)

Uca pugilator, the sand fiddler crab, constructs two kinds of burrows in protected, sandy upper-intertidal and supratidal substrates on the west coast of Florida. Temporary burrows are built and used as a refuge by non-breeding crabs during high tide periods and at night when crabs cease feeding in the intertidal zone. Breeding burrows are constructed and defended by courting males and are the site of mating, oviposition and the incubation of eggs by females. Up to three ovigerous females may be accommodated in a single breeding burrow, each female sequestered in a separate terminal chamber. The construction and defence of burrows specialized for breeding may be an adaptive response by males to the preferences females exhibit when selecting a breeding site.     

Model of burrow selection predicts pattern of burrow switching by Leach's Storm‐Petrels

Patterns of nest site selection exhibited at the scale of a population should result from initial preferences of individuals occupying nest sites as well as preferences exhibited by individuals moving between nest sites. We tested whether nest‐site preferences measured at the population scale were predictive of patterns of burrow switching by Leach's Storm‐Petrels (Oceanodroma leucorhoa), a long‐lived seabird that nests in underground burrows. Breeding pairs generally choose from the pool of available existing burrows rather than constructing new burrows, and a portion of the burrows in a colony remains unused in any breeding season. We quantified burrow preference at a colony on Kent Island, New Brunswick, over four breeding seasons. We used a classification and regression tree analysis to build a predictive model of nest‐site selection. Preferentially occupied burrows were drier, longer, had larger nest chambers, and were in areas of higher burrow density. To measure preferences during burrow switching, we tracked individuals that switched burrows, comparing characteristics of the burrows in which these birds were originally found to those they inhabited at the end of the study period. Characteristics preferred by switching individuals were a subset of those observed at the scale of the population; individuals moved to burrows that were drier, longer, and had larger nest chambers. Our results show how preferences of individuals that move between nest sites contribute to nest site preferences exhibited at the population scales commonly tested.     

Olfactory navigation to the nesting burrow in Leach's petrel (oceanodroma leucorrhoa)

Visual, auditory, and olfactory navigation in the homing behaviour of Leach's petrel to the nesting burrow were investigated. Petrels returning to their burrows at night hovered above the thick spruce-fir canopy in the vicinity of the burrow before plummeting to the forest floor a few metres downwind of their burrows. They then walked upwind to their burrows. Birds landed closer to, and followed more circuitous routes to, their burrows in still air than in a wind. They failed to avoid obstacles in the path to burrows, often failed to locate accurately burrow entrances on first trial, and vocalized only after entering the burrow. In a Y-maze olfactorium, captive breeding petrels chose an air current coming from their own nest material in preference to one from similar materials collected on the forest floor. In the same apparatus, birds did not respond positively to air currents from their own stomach oil or preen gland oil. Petrels taken from burrows and released that same night did not return within a week if their external nares were plugged or if their olfactory nerves were transected. They did return if not operated on or if only subjected to sham operations. These results support an olfactory guidance system in burrow location and argue against visual or auditory guidance.     

Non-breeding behaviour of Magenta Petrels Pterodroma magentae at Chatham Island, New Zealand

Magenta Petrels Pterodroma magentae were caught at light-attraction stations on southwest Chatham Island, New Zealand, and most were fitted with transmitters. Of 52 captured since 1993, 71% were males, and all 36 tracked adequately proved to be non-breeders in the breeding season of capture. Our data indicated no sex bias in their probability of being captured at lights. Males provided 86% of trackings, and 87% of trackings of birds flying over the breeding area were males. Males landed 118 times; females 13 times. Only males were found on the ground, by night and day, apparently unassociated with burrows (three with and ten without transmitters), but subsequently digging burrows ( n  = 8). Of 19 birds banded as fledglings up to 2000, males were first recaptured nearing 4 years old (at lights and on the ground) and a female nearing 6 years old (in burrow). Among 37 fledglings, the sex ratio was even. Nine tracked males occupied burrows, as did two females, but the latter were older recaptures (10+ and 25+ years old). It appears that only males claimed existing, or dug new, burrows. They then attracted a mate to the burrow by means unknown, but from among females frequenting an inshore courtship area near the colony, or occasionally flying over the colony, at night. Females established in burrows, but then losing their mate, were able to re-mate there, by calling from near the burrow or by attracting a mate in flight or from the postulated inshore courtship area. Both sexes sometimes took years to pair or re-mate, possibly reflecting the dearth of available mates.     

Utilization of habitat by the northern hairy-nosed wombat Lasiorhinus krefftii

The small population of northern hairy-nosed wombats in Epping Forest National Park is the last one known. The wombats construct their burrows in deep sandy soil, and feed through an open woodland with a grassy understorey. Individual wombats used small home ranges, with 70% core areas averaging 5.8 ha, and total range areas averaging around 25 ha. Their nightly emergences from burrows were timed to avoid extreme above-ground temperatures. Total activity varied from 2 to 6 hours above ground per night, and was greatest during late winter and early spring, when pasture productivity had been very low for around nine months. There was no evidence of any tendency for body condition or growth to fluctuate in response to variations in seasonal conditions. The ability of this species to maintain condition during harsh seasons while adopting conservative ranging behaviour is evidence of adaptations for the minimization of energy expenditure and the utilization of poor-quality forage. Management of the Park should attempt to see that consistent reserves of forage are maintained close to burrows throughout the year.     

Foraging activity of the sand beach isopod Scyphax ornatus Dana

Abstract

The terrestrial isopod Scyphax ornatus lives on exposed sand beaches. Adult isopods spent the daytime in burrows near the high water mark and made nightly foraging excursions over the uncovered middle beach. Hourly records of their night time distribution showed that Scyphax congregated near the water’s edge during the last 4 h of flood tide, where they fed on carrion. Insects (mostly drowned honey bees) were the main food item, but coelenterates, amphipods, crabs, and goose barnacles were also eaten. During ebb and early flood tides Scyphax occurred at low densities over the uncovered middle beach. Analysis of the distribution of large and small food items on the beach showed that by feeding during the flood tide, Scyphax exploited a rich concentration of carrion that accumulated in the swash zone and that was moved slowly up the beach by the incoming tide.     

Endogenous rhythm in activity of an estuarine amphipod,Talorchestia longicornis

The biological rhythm in activity of the supratidal amphipod Talorchestia longicornis Say was determined under constant conditions. Surface activity was monitored with a time-lapse video system under red light and assessed as the number of animals emerging from their burrows and active on a sand substrate at 0.5?h intervals. The amphipods had a circadian rhythm in which they were active at the time of night at the collection site. The rhythm could be entrained by a light?:?dark cycle and had an average free-running period of 23.7?h. Activity also appeared to be related to tidal times at the collection site because, under constant conditions, surface activity was suppressed at the time of nocturnal high tide and increased at the time of nocturnal low tide. The rhythm is functionally significant for foraging at night to avoid visual predators, desiccation and high temperatures.     

Lunar synchrony in the reproduction of the Moluccan Megapode Megapodius wallacei

The Moluccan Megapode Megapodius wallacei uses heat generated by the sun to incubate its eggs. It buries the eggs deep in the sand of sun-exposed beaches and open sandy areas on islands in the Moluccas, Indonesia. The eggs are laid at night and left to incubate for two to three months without parental care. We present evidence that the Moluccan Megapode exhibits lunar synchrony in the timing of egg-laying, its spatial distribution of egg burrows and in its behaviour at communal nesting grounds. More Moluccan Megapodes visit the nesting grounds on bright nights than during the new moon. Data collected on the spatial distribution and depth of egg burrows also exhibit lunar periodicity. On moonlit nights, the birds excavate burrows in communal groups and spend longer at the nesting ground digging deeper burrows. Lunaphilia and lunar periodicity of reproduction are rarely documented in birds. We discuss possible explanations for these behaviours in the Moluccan Megapode.     

Endogenous rhythm in activity of an estuarine amphipod, Talorchestia longicornis

The biological rhythm in activity of the supratidal amphipod Talorchestia longicornis Say was determined under constant conditions. Surface activity was monitored with a time-lapse video system under red light and assessed as the number of animals emerging from their burrows and active on a sand substrate at 0.5 h intervals. The amphipods had a circadian rhythm in which they were active at the time of night at the collection site. The rhythm could be entrained by a light : dark cycle and had an average free-running period of 23.7 h. Activity also appeared to be related to tidal times at the collection site because, under constant conditions, surface activity was suppressed at the time of nocturnal high tide and increased at the time of nocturnal low tide. The rhythm is functionally significant for foraging at night to avoid visual predators, desiccation and high temperatures.     

Round-the-clock homing behavior of a subsocial shield bug, Parastrachia japonensis (Heteroptera: Parastrachiidae), using path integration

Females of the subsocial shield bug, Parastrachia japonensis (Parastrachiidae), are central-place foragers, collecting drupes for their young from nearby host trees by walking along the forest floor both during the day and at night. Because burrows are often some distance from the drupe-shedding tree, the bugs must repeatedly leave their burrows, search for drupes, and return to the burrows. After a bug leaves its burrow, it searches arduously until it encounters a drupe. When a drupe is obtained, the bug always takes the shortest route back to its burrow. It has been clarified that this bug utilizes path integration during diurnal provisioning excursions. In this paper, we examined nocturnal behavior and some parameters of the path integration utilized by P. japonensis. There were no observable differences between day and night in the patterns of foraging and direct-homing behavior. When the bug was displaced to another position during the day or night, it always walked straight toward the fictive burrow, the site where the burrow should be if it had been displaced along with the bug, and then displayed searching behavior in the vicinity of the fictive burrow. The distance of the straight run corresponded accurately with a straight line between the burrow and the place where the bug obtained the drupe. These results indicate that P. japonensis orients toward the burrow using path integration both during diurnal and nocturnal provisioning behavior.     

Size as a Factor Influencing the Ownership of Copulation Burrows by the Ghost Crab (Ocypode ceratophthalmus)

On Cousin Island, Seychelles, male ghost crabs mostly constructed their copulation burrows around new moon. The burrows were sited below the high tide mark and therefore only lasted until washed away by the incoming tide. Large males were able to defeat small males in contests for burrows and so, to reduce the risk of eviction, small males built their burrows later on the ebbing tide than large males, after the period when fights for burrows were most frequent. There was also evidence that small males built their burrows on stretches of beach presumed to be inferior, because the burrow density was lower.     

Determination of the absolute visual threshold of a nocturnal seabird, the Common Diving Petrel Pelecanoides urinatrix

Many of the smaller burrowing petrels are active at their colonies during the night. How they find their nesting burrows in the open terrain of an oceanic island or in the even more visually-taxing gloom under a forest canopy (Grubb 1974 and references therein) is a feat which has long intrigued naturalists (Lockley 1942). There is experimental evidence that vision is important in burrow location by the Manx Shearwater Puffinus puffinus (Brooke 1978, James 1986), while olfactory homing by Leach's Petrel Oceanodroma leucorhoa has also been suggested by Grubb (1974).
Additionally it seems likely that a number of petrel species catch a significant fraction of their food at night (Imber 1973, Prince & Francis 1984). Many of the squid presumed to be caught then are not bioluminescent (Imber 1973, Clarke et al. 1981), so their detection presumably demands good night vision. In the context of these observations, the dearth of information on the visual abilities of petrels is remarkable.
The present study investigated the absolute visual threshold of the Common Diving Petrel Pelecanoides urinatrix. Probably because the species is small (c. 130 g) and so vulnerable to predators such as Sub-antarctic Skuas Catharacta antarctica , it is strictly nocturnal at breeding colonies (Thoresen 1969, Payne & Prince 1979). It nests in burrows that are often located under tussock grass Poa spp. Whether the birds catch their crustacean prey (Payne & Prince 1979) by day or night is not known.     

Thermal biology, torpor, and activity in free-living mulgaras in arid zone Australia during the winter reproductive season

Little is known about the energy conservation strategies of free-ranging marsupials living in resource-poor Australian deserts. We studied activity patterns and torpor of free-living mulgaras (Dasycercus blythi) in arid central Australia during the winter of 2006. Mulgaras are small (approximately 75 g), nocturnal, insectivorous marsupials, with a patchy distribution in hummock grasslands. Mulgaras (six males, three females) were implanted intraperitoneally with temperature-sensitive transmitters and monitored for 6-55 d. Temperature profiles for different microhabitats and the thermal properties of soil and a number of burrows were also measured. Air temperature ranged from -3 degrees C at night to 30 degrees C during the day. Although burrows buffered temperature extremes, the thermal diffusivity of the sandy soil was high, and many burrows were shallow. Hence, soil and burrow temperatures averaged about 15 degrees C. The activity of mulgaras was often restricted to a few hours after sunset, before they retired into their burrows. Mulgaras employed torpor frequently, often entering torpor during the night and arousing around midday, with arousals occurring later on cooler days. Shallow burrows allowed cooling below mean T(soil). Consequently, body temperatures as low as 10.8 degrees C were observed. The longest torpor bout was 20.8 h. Torpor patterns changed seasonally and differed between males and females. From June to August, females entered torpor almost daily despite mating and gestation, but from the end of the gestation period onward, they remained normothermic. In contrast, males showed only shallow and short torpor during the mating season, but from mid-July, a transition to more frequent and deeper torpor resembling that of females was observed. Apparently, in both sexes, the reproductive effort entails energetic costs, but torpor, as an energy-saving mechanism, and reproduction are not exclusive in mulgaras. In a resource-poor environment during the least productive part of the year, frequent torpor seems to provide the means to compensate for the increased energetic costs associated with reproduction.     

Records of hypogeous mycorrhizal fungi in the diet of some Western Australian bolboceratine beetles (Coleoptera: Geotrupidae, Bolboceratinae)

In order to assess the possible contribution of bolboceratine beetles to the dispersal of mycorrhizal fungal spores, faeces and/or gut contents of adults of several species and genera obtained from burrows or collected at lights at night were examined microscopically. Two species of Blackbolbus ( frontalis and fucinus ) were found to have fed on different species of hypogeous sporocarps (truffles). Furthermore, adults of Bbo. frontalis were found in burrows with truffles of the genera Amarrendia , Hysterangium and Scleroderma . Specimens of some Blackburnium , Bolboleaus and Bolborhachium species, on the other hand, were found to have ingested diffuse glomeralean mycelium and spores along with varying quantities of soil. Limited evidence of broad-scale distribution of spores was obtained. Some Scleroderma truffles found in burrows of Bbo. frontalis were honeycombed and inhabited by numerous nitidulid beetles identified as Thalycrodes mixta . Two truffles identified as Hysterangium found in soil close to a burrow of Bbo. frontalis were infested with nematodes.     

Topographic distribution and daily activity of the European ground squirrel population in Bugacpuszta, Hungary

Factors affecting the population density and daily pattern of activity of the European ground squirrelSpermophilus citellus (Linnaeus, 1766) were studied in two habitats of the Kiskunság National Park, Hungary. One habitat was dominated by sandy and the other by salty grassland. Population densities were estimated by counting ground squirrel burrow entrances in sample areas with different microhabitat characteristics. Three categories (elevated, level and depressed) were used to describe the spatial distribution of burrows according to microtopography. Daily activity was evaluated by counting the ground squirrels visible on the surface and registering their alarm calls. The highest proportion of ground squirrel holes was found on elevations in the two habitats. Ground squirrels showed a similar daily activity pattern in different areas and in the same season in consecutive years. The daily activity consisted in a morning peak, a midday pause and a less regular afternoon activity period. Human activity had no direct effect on the daily activity pattern. Emission of alarm calls peaked in June, when litters emerge from the maternal burrows.     

Ecological Aspects of Some Coral-Boring Gastropods and Bivalves of the Northwestern Red Sea

More than 17 molluscan species were obtained from burrows incoral substrata at Al-Ghardaga (Hurghada on maps) on the RedSea coast, six of which in particular bore into livingcolonies.The species reported in this paper belong to the families Mytilidae,Coralliophilidae, and Gastrochaenidae. The direction of boringin living corals is to the outside, the borers keeping pacewith the growing coral layer to maintain their burrows open.Coral growth is generally of a higher rate than that of borers,and burrows are accordingly mostly much larger than their inhabitants.There is evidence in such cases that burrows form initiallyby growth of coral around the settling young. Boring of Lithophagaspecies is mostly due to the abrasive action of the shell whichmoves straight and posteroventrally without any rotation. Incoralliophilids,boring is also executed mechanically by the turning movementsof the shell. Boring in dead coral is directed inwards, andburrows are nearly as large as the borers. The latter avoidthe blocking of their burrows (e.g., by a living coral incrustation)either by great siphonal extension (Rocellaria) or the freeends of the shell may be strengthened to maintain the capabilityof boring in the opposite direction (Lithophaga laevigata).Both L. luevigata and Modiola chmamomeus bore mainly mechanicallyby the rocking movements of the shell. Chemical boring is stilla possibility,particularly in the posterior narrow region ofburrows of Modiola lodging the extended pallial siphons whichare deprived of any effective mechanical devices for boring.Therole of boring algae in rarefying bored coral material hasalso to be included as an indirect chemical factor.