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.     

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.     

Recognition of burrow's olfactory signature in blue petrels, Halobaena caerulea: an efficient discrimination mechanism in the dark

Previous work has shown that blue petrels need olfaction to home. We investigated whether they also recognize an olfactory signature of their own nest. We performed T-maze experiments in which maze arms were connected with the subject bird's burrow and with the burrow of a conspecific neighbour. Of 23 birds, 16 were able to recognize the arm leading to their own burrow. In a second experiment, we positioned the maze in front of the subject's burrow but the maze arms were closed and did not enter the burrow. Consequently, no burrow odours could be sensed by the bird. In this case, 85% of birds (17 of 20) failed to choose, suggesting that petrels were not motivated to choose by positional cues in the absence of odour cues. We explored this idea further by performing a homing experiment whereby homing birds had to relocate an artificially displaced burrow entrance. Blue petrels homed, ignoring the natural burrow entrance and using the new artificial one. The ability to smell their own burrow allows blue petrels to return to the colony at night and to find the correct nest.     

Incubation failure and nest abandonment by Leach's Storm‐Petrels detected using PIT tags and temperature loggers

ABSTRACT The nocturnal activity of burrow‐nesting seabirds, such as storm‐petrels and shearwaters, makes it difficult to study their incubation behavior. In particular, little is known about possible differences in the incubation behavior of adults at successful and unsuccessful nests. We combined the use of passive integrated transponder (PIT) technology and nest‐temperature data loggers to monitor the incubation behavior of 10 pairs of Leach's Storm‐Petrels (Oceanodroma leucorhoa). The mean incubation bout length was 3.31 ± 0.59 (SD) days for individual adults at successful nests (N= 4) and 1.84 ± 1.16 d for individuals at unsuccessful nests (N= 6). Mean bout length for pairs in successful burrows (3.51 ± 0.56 d) did not differ significantly (P= 0.07) from that for pairs in unsuccessful burrows (1.80 ± 1.20 d), perhaps due to one failed nest with a high mean bout length (4.15 d). The total number of incubation bouts per parent (4.3 ± 1.9 bouts) did not differ with hatching success. Adults whose nests failed repeatedly exhibited truncated incubation bouts (< 12 h) prior to complete nest failure and were more likely than successful parents to make brief visits to nearby, occupied nesting burrows. Our results suggest that the decision by Leach's Storm‐Petrels to abandon a nest is not an abrupt one. Rather, failed nesting attempts may be characterized by truncated incubation bouts where individuals pay the energetic cost of travel to and from the burrow, but do not remain long enough to successfully incubate the egg.     

Microhabitat and rhythmic behavior of tiger beetle Callytron yuasai okinawense larvae in a mangrove forest in Japan

Mangrove forests are regularly flooded by tides at intervals of approximately 12.4 h (tidal rhythm). Larvae of the tiger beetle Callytron yuasai okinawense in a mangrove forest made shallow burrows in mounds up to 1 m in height constructed by the mud lobster Thalassina anomala. No larval burrows were observed on the forest floor, which was very muddy even during low tide. Some larvae plugged the burrow openings before they were submerged at high tide. The mean interval between consecutive burrow plugging events was 12.37 h, which is similar to the period of tidal cycles. Nine out of 30 larvae plugged the burrow openings even when the burrows did not become submerged. Plugging behavior may be governed by an endogenous biological clock, or may be a response to exogenous information about tidal level (e.g. moisture seeping through the ground).     

青藏高原东缘高寒森林小型兽类地表洞穴选择与生境特征

高寒森林地表的小型兽类洞穴是生态系统重要的景观特征,对于认识小型兽类的分布格局及其生态功能具有重要意义.为此,以青藏高原东缘典型高寒森林生态系统小型兽类洞穴为对象,于2015年夏季(7—9月)研究了其地表分布与生境特征.结果表明: 小型兽类洞穴平均洞口密度为182.8个·hm^-2,不同森林植被类型显著影响洞穴密度,表现为针叶林(328.6个·hm^-2)>针阔混交林(160.0个·hm^-2)>灌木林(125.0个·hm^-2)>阔叶林(81.5个·hm^-2)>竹林(66.7个·hm^-2). Mann-Whitney U Test和主成分分析表明,小型兽类栖息样地的乔木郁闭度、乔木均高、乔木胸径、乔木密度、地表植被盖度、倒木密度、倒木覆盖度、灌木均高都显著大于非栖息样地;乔木因子是决定小型兽类生境选择的首要因子,贡献率最大(44.8%),其次是倒木因子(23.2%)和灌草丛因子(13.9%).说明高寒森林地表有明显的小型兽类洞穴分布,其分布格局主要受植被和倒木的影响.     

How Do Carpenter Bees Recognize the Entrance of their Nests?: An Experimental Investigation in a Natural Habitat1

Carpenter bee females (genus Xylocopa) enter only their own nests. They can be found in the same burrow over a period of months, regardless of whether they arc living singly or aggregated in close vicinity. The aim of this study was to investigate and to clarify which sensory systems are responsible for the recognition of the nest. Females of three different African species were tested in their natural habitat. Following alteration in the immediate visual surroundings of either the entrance or the entire dwelling stem, bees behaved as they did in undisturbed situations and entered their nests. Furthermore, a relative dislocation of the entrance within the dwelling stem or a displacement of the whole stem within a restricted range had no effect on the recognition of the burrow. When the entrance was plugged by foam rubber the bees landed only after extended searching. When the entrance was closed by a strip of scotch tape the bees searched for several minutes, departed, then returned and searched again with the same result. The bees showed no indications that they recognized their burrow. These results strongly support the conclusion that the bees recognized their burrows primarily or exclusively by olfactory cues, and, furthermore, that individual odors were involved. The possible contributions of different sensory systems for the recognition of the nest and the possible biological function of the use of olfactory cues are discussed.     

Use of local cues in the night-time navigation of the wandering desert spider <Emphasis Type="Italic">Leucorchestris arenicola</Emphasis> (Araneae,Sparassidae)

Adult male Leucorchestris arenicola can walk round-trips of several tens of meters in search of females. Most excursions end with the spiders returning to their burrow. For small animals homing over distances of several meters is theoretically impossible without the aid of external cues. It was investigated, whether the spiders use local cues or they rely solely on global cues. Individually marked male spiders were captured during their excursions and displaced several meters inside an opaque box. Ten out of twelve displaced spiders returned to their burrows. This shows that the male L. arenicola are using local cues during their homing, as the comparatively small displacement distances could not be detected by means of global, e.g. celestial cues. In order to test whether the spiders could be using olfactory guidance, the burrows were displaced by 2 m while the spiders were out on their journeys. In 12 out of 15 experiments, the spiders did not find their burrows. These results show that the burrows do not function as olfactory beacons for the homing spiders.     

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.     

Territorial Pheromones of Female Red-backed Salamanders

Pheromones provide an important source of communication during social interactions of caudate amphibians. To further examine their use in territorial defense, we performed a laboratory experiment to test the hypothesis that non-courting female red-backed salamanders (Plethodon cinereus) deposit pheromones in or on fecal pellets, as males are known to do during territorial advertisement. Four conditions were tested: (1) a burrow marked with a female's own pellet vs. a burrow marked by a conspecific female's pellet, (2) own vs. unmarked burrows, (3) conspecific vs. unmarked burrows, and (4) paired unmarked burrows as a control. Females nose-tapped (for olfactory cues) their own and conspecific pellets about equally. However, they spent significantly more time in both threat and submissive behavior toward the conspecific pellets and spent significantly more time in their own marked burrows. We infer that female P. cinereus do deposit pheromones in or on fecal pellets and that these pellets may be used to advertise territories. The behavioral responses of females toward pellets of other females were more aggressive than those of males (in a previous study) toward pellets of other males.     

Salamander territoriality: pheromonal markers as advertisement by males

A laboratory experiment was performed to test the hypothesis that male red-backed salamanders (Plethodon cinereus) use pheromones contained in faecal pellets to identify male-marked territories. Each of 25 males was tested randomly under four conditions: (1) a burrow marked with its own faecal pellet versus one marked with a conspecific's pellet; (2) own-marked versus surrogate-marked burrows (the surrogate being a pellet of wadded paper); (3) conspecific-marked versus surrogate-marked burrows; and (4) a control of two surrogate-marked burrows. Males spent significantly more time in own-marked than in conspecific-marked burrows and significantly more time in surrogate-marked than in conspecific-marked burrows. Males favoured own-marked over surrogate-marked burrows. No position bias was found in the control. Males spent significantly more time nose-tapping (olfactory sampling) to a conspecific's pellet when it was paired with a surrogate but showed no differences in the other three tests. Significantly more time was spent in a submissive posture in front of the conspecific-marked burrow than in front of either their own-marked or the surrogate-marked burrows; no difference was found between own-marked versus surrogate-marked burrows or in the control. Time spent in the threat posture did not differ significantly between burrows in any condition. These data permit the inferences that males of P. cinereus use faecal pellets to mark and identify territories, avoid or display submissively toward burrows marked by conspecific males, and prefer own-marked shelters.     

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.     

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.     

Mole activity in woodlands, fens and other habitats

Monks Wood, a deciduous wood of 155 hectares on clay soil, has an estimated population of 400 moles. There is an anastomosing system of permanent burrows, and when a mole is trapped its area of burrow is soon occupied by another animal. Little new digging occurs, except in winter, after frost has driven the soil fauna deeper into the ground. The burrows usually act as pit-fall traps for the food. Young animals migrating in summer may live more superficially, in tunnels in moss and grass, but survivers usually move into a permanent tunnel system by autumn.
Woodwalton Fen has an easily worked peat soil, and few earthworms. Here moles burrow at all seasons, presumably needing an extensive burrow system to catch sufficient food. In times of flood, the moles leave submerging ground but return very soon after the water subsides. They probably swim across flooded areas but iis yet we do not know if the same animals return after floods to the same burrows.
Moles are not good indicators of soil fertility, particularly as many mole heaps are made by few moles in poor soil, and fewmew heaps may appear in good soil with permanent burrows. We do not understand why there are so few moles in some apparently suitable pasture, with high worm populations, or how others manage to obtain sutficient food in infertile areas.     

Influence of topography on the location and density of armadillo burrows (Dasypodidae: Xenarthra) in the central Amazon, Brazil

Armadillos (Dasypodidae: Xenarthra) are the principal group of burrow-excavating mammals in Amazonian forest. Little is known about how the landscape's physical characteristics influence where these organisms choose to construct their burrows. We measured topographic characteristics of armadillo burrow placement and evaluated whether these variables affect overall burrow density. Our study took place on the study sites of the Biological Dynamics of Forest Fragments Project in the central Amazon, Brazil. To determine if armadillos exhibit habitat use preferences in constructing their burrows, we quantified the declination and elevation of available terrain along transect lines on our study sites and compared this with the characteristics of areas containing burrows. We also tested whether topographic variables were related to burrow density. Armadillos preferentially build burrows on low elevation, inclined terrain, and declination was positively related to burrow density. Low, inclined areas correspond to slopes next to stream basins. It may require less effort for armadillos to excavate these areas, while also providing proximity to water. The results of this study indicate that topographic information is important to consider when using burrows to estimate habitat use and density of armadillos in terra-firme forests of the central Amazon.     

The vocal systems of two nocturnal burrowing petrels, the White-chinned Procellaria aequinoctialis and the Grey P. cinerea

I studied the calls of White-chinned Petrels Procellaria aequinoctialis and Grey Petrels P. cinerea at the Prince Edward Islands in the Southern Ocean. White-chinned Petrels gave two calls. One, the Wheezy call, was usually given from within breeding burrows, was given in response to playback of strange (= non-mate) calls, and probably served a burrow defence function. The other call, the Rattle call, was uttered roughly as often on the ground as from within the burrow. This call was mostly given by males and probably served as sexual advertisement. The one identified call type of the Grey Petrel was given in the same circumstances as the Wheezy call of the White-chinned Petrel.
In both species there was evidence of mate recognition of calls. Birds tended to remain silent to the playback of the mate's call, whereas they responded vocally to strange calls.
This vocal system, where both sexes share two call types but where sexual dimorphism in call is absent, has not been described before for petrels. Possible reasons for the variation in petrel vocal systems are discussed.     

The microenvironment of house mice on Marion Island (sub-Antarctic)

On Marion Island, house mice ( Mus musculus) establish burrow systems that range from unbranched corridors 0.5 m long with a single chamber (in some instances without a chamber) to complexly branched systems extending over an area of up to 4 m² and containing up to four chambers. Total underground area occupied by burrow systems (chambers plus corridors) was from 5 to 23 m² ha^-1, corresponding to burrow-system volumes of 250-1,300 dm³ ha^-1. In autumn, about three-quarters of chambers contained small food caches. Most (87%) entrances to burrow systems faced away from prevailing winds, especially winds that bring snow, hail or rain. Seasonal and diurnal temperature variations in burrows are considerably dampened (daily minimum in burrows seldom drops below 2°C), compared with the air just above the vegetation canopy. Over the whole year, total night-time warmth in a burrow (heat sum, 24,883 degree hours) was 53% greater than at the top of the canopy (16,317 degree hours). Burrows' entrances are generally connected above ground by runways (paths and tunnels through the vegetation). Runways also represent a warmer environment than the air above the canopy during the breeding season at night (13,466 degree hours at the runway surface compared with 11,900 degree hours at the top of the canopy). House mice, which are living close to their physiological limits, temperature-wise, on Marion Island thus evade the worst extremes of the island's climate by constructing burrows and above-ground runways and this is an important factor in their survival.     

Seismic signal transmission between burrows of the Cape mole-rat,Georychus capensis

Summary Both seismic and auditory signals were tested for their propagation characteristics in a field study of the Cape mole-rat (Georychus capensis), a subterranean rodent in the family Bathyergidae. This solitary animal is entirely fossorial and apparently communicates with its conspecifics by alternately drumming its hind legs on the burrow floor. Signal production in this species is sexually dimorphic, and mate attraction is likely mediated primarily by seismic signalling between individuals in neighboring burrows. Measurements within, and at various distances away from, natural burrows suggest that seismic signals propagate at least an order of magnitude better than auditory signals. Moreover, using a mechanical thumper which could be triggered from a tape recording of the mole-rat's seismic signals, we established that the vertically-polarized surface wave (Rayleigh wave) propagates with less attenuation than either of the two horizontally-polarized waves. Thus, we tentatively hypothesize that Rayleigh waves subserve intraspecific communication in this species.Abbreviations PPM pulses per min - SB simulated burrow - SD standard deviation - SPL sound pressure level     

Observations on the activity and thermoregulation of the tuatara,Sphenodon punctatus (Reptilia: Rhynchocephalia), on Stephens Island

Abstract

Observations on Stephens Island, Cook Strait, in December 1978 show that although the tuatara is generally most active at night, many animals spend much of the day at or beyond burrow entrances, apparently to increase their body temperature. During the day, tuataras tend to move further from burrows which are under shaded forest than from those in open pasture. By day, mean body temperatures (±SE) ranged from 17.2±0.5°C in forest shade to 24.6±1.1°C in full sunlight; the maximum body temperature recorded was 26.3°C. The significance of these observations is discussed.     

Testing the use of infra‐red video cameras to census a nocturnal burrow‐nesting seabird,the European Storm Petrel Hydrobates pelagicus

Accurate population estimates are important for monitoring the conservation status of species, but nocturnal burrow‐nesting seabirds are notoriously difficult to count. Storm petrel species (Hydrobatidae) are particularly challenging, as burrow entrances are indistinct and response rates to playback low and variable, leading to imprecise population estimates and poor ability to detect trends. Playback is also labour‐intensive, requiring several days of calibration trials to determine site‐ and year‐specific response rates. To test the viability of using infra‐red digital video technology to census storm petrels, we conducted a trial on European Storm Petrels Hydrobates pelagicus at their largest UK colony, Mousa (Shetland). Hourly activity rates recorded from infra‐red filming accurately predicted the number of Apparently Occupied Sites (AOS), but this relationship was stronger in natural habitats (boulder‐beach, rocks and scree) than in walls, where between‐night variation was high due to poor and variable image quality, as well as the flight behaviour of Storm Petrels around vertical structures. Few filming attempts failed completely, but image quality was poor on dark nights with rain or fog, and deteriorated during the season as night‐length increased. Playback accurately predicted AOS density in natural habitats, but overestimated total AOS in walls by 38%. Simulations suggest that for the same fieldwork sampling effort, infra‐red filming will generate slightly more precise AOS estimates compared with playback. Better illumination using infra‐red floodlights would increase detection rates on dark nights, probably resulting in greater precision, but the large amount of expensive equipment and reviewing time required currently make infra‐red filming costly and inefficient relative to playback. However, we recommend its use at sites that cannot otherwise be surveyed safely, or where disturbance is a concern.