Firmground crustacean burrow systems (Glossifungites ichnofacies) in marine shelf deposits,Paleocene Clayton Formation,Alabama, USA

The Paleocene (Danian) Clayton Formation of western Alabama, USA, includes multiple marine shelf parasequences, each comprising a relatively thick marl, capped by a thin limestone, the latter variably reflecting marine flooding episodes. The marls host relatively large firmground burrow systems that penetrate 50–60 cm beneath, and are cast by, superjacent limestones. Excavation of two partially exposed burrow systems – one beneath a highstand parasequence-bounding flooding surface and the other beneath an overlying coplanar sequence boundary/transgressive surface (SB/TS) – reveals complex, primarily horizontal, irregularly branching networks. The former, allied with Thalassinoides paradoxicus, lacks wall bioglyphs, whereas the latter, allied with Spongeliomorpha iberica, is characterized by pervasive, mainly rhombohedral wall bioglyphs that reflect a relatively more firm substrate. Contrasts between these burrow systems are consistent with sequence stratigraphical context and inferred differences in the mechanism and magnitude of depositional hiatuses responsible for firmground development. Both excavated burrow systems likely represent cumulative structures produced by multiple organisms over extended periods of time. The cumulative nature and potential taphonomic biases associated with these and comparable burrow systems in the stratigraphical record preclude confident interpretation of tracemakers and their behaviours. The Clayton burrow systems likely were produced by one or more species of decapod crustacean that engaged in suspension-feeding, surface detritus feeding, gardening or some combination thereof.     

Passive irrigation and functional morphology of crustacean burrows in a tropical mangrove swamp

Flushing measurements and a resin cast of a burrow inhabited by Sesarma messa and Alpheus cf macklay were taken from a Rhizophoraspp. forest. The burrow had 9 openings and occupied a swamp surface area of 0.64 m². Passive irrigation of the burrow was investigated by recording change in conductivity of burrow water in a chamber 45 cm below the swamp surface during tidal inundation of the swamp. The chamber was completely flushed within approximately one hour, i.e. by a single tidal event. Burrow morphology was determined by means of resin casting. The investigated burrow was of discrete structure, with an overall depth of 1.2 m and a total volume of 68 l, i.e. ca. 9% of the volume of swamp soil. The below ground surface area of chambers and tunnels was 3.8 m². The mean and maximum chamber/tunnel diameter was 7 cm and 11 cm respectively. The soil in the close vicinity of the burrow was extensively penetrated by roots, and any two parts of the burrow were located no further than 20 cm away from each other. By reducing diffusion distances within the soil and by being well flushed, the burrows provide an efficient mechanism for removal of excess salt accumulated in the soil around mangrove roots due to exclusion.     

Burrow use by Tibetan Ground Tits Pseudopodoces humilis: coping with life at high altitudes

The Tibetan Ground Tit Pseudopodoces humilis is a high-altitude passerine endemic to the Tibetan Plateau. A 4-year study in alpine meadows in Northern Tibet at 4300 m asl demonstrated that rather than using Pika Ochotona spp. holes as previously reported, the birds excavated one nest burrow themselves in spring and another after breeding, which they used for roosting in winter. Both the nesting and winter-roosting burrows comprised a straight tunnel leading to an ellipsoid chamber. There were no significant differences in placement or structural characteristics between the two types of burrows, except that winter-roosting burrows had a significantly smaller entrance diameter. Most burrows were 100–160 cm long and their chambers 20–40 cm deep. Tibetan Ground Tits tended to maximize the thermal benefits of their burrows by adjusting their spatial and structural characteristics in response to local solar radiation and wind regimes. Burrows tended to be oriented towards the sun and away from prevailing winds, presumably to maintain burrow temperature. Longer tunnels could function to save heat from solar radiation or reduce wind-disturbance, while shorter tunnels allow chambers to be warmed sooner in situations where wind potentially reduced soil temperatures. The thermal benefits to the birds of burrow architecture are likely to play a crucial role throughout the year in these extreme alpine environments.     

Burrowing behaviour of the New Zealand indigenous earthworm

Mature Octochaetus multiporus in pots of sieved soil created a network of burrows with a diameter of about 10 mm which did not open to the surface. Several chambers 15 to 20 mm wide and 20 to 50 mm long were found within the burrow network; some worms were found curled within these chambers which also contained a quantity of loose cast material. Octochaetus multiporus responded to the presence of plants by burrowing nearer to the surface under white clover and nearer to bottom of the pot under chicory.     

The frequency and fitness consequences of communal breeding in a natural population of burying beetles: a test of reproductive skew

Abstract.  1. Reproductive cooperation occurs in diverse taxa and a defining characteristic of these social systems is how reproduction is shared. Both male and female burying beetles ( Nicrophorus spp.) facultatively form associations to bury a carcass and rear a single brood, making burying beetles a model system for testing skew theory.
2. In this study, 50% of 40–45 g carcasses and 75% of 55–60 g ones were buried by more than one male and/or female Nicrophorus tomentosus .
3. Females were significantly more likely to cooperate on 55–60 g carcasses than on 40–45 g ones.
4. Analysis of parentage of 13 broods using microsatellite loci as genetic markers showed that maternity analysis of only 2% of the young excluded all females captured leaving the brood chamber after burial. Males previously mated with resident females or displaced by resident males fathered 7% of the young.
5. The male and female remaining the longest were usually the parents of the most offspring, and reproductively dominant individuals also tended to be the largest.
6. Although all but two or three individuals that helped to bury the carcass produced some offspring, reproduction was often not shared equitably. Reproduction of females was significantly skewed on six of nine 40–45 g carcasses but shared fairly equitably on all three 55–60 g ones. Reproduction was skewed among males on 7 of 10 broods.
7. Both males and females relinquished a greater proportion of the brood as the days of assistance from all consexuals increased.     

Nest Enlargement in Leaf-Cutting Ants: Relocated Brood and Fungus Trigger the Excavation of New Chambers

During colony growth, leaf-cutting ants enlarge their nests by excavating tunnels and chambers housing their fungus gardens and brood. Workers are expected to excavate new nest chambers at locations across the soil profile that offer suitable environmental conditions for brood and fungus rearing. It is an open question whether new chambers are excavated in advance, or will emerge around brood or fungus initially relocated to a suitable site in a previously-excavated tunnel. In the laboratory, we investigated the mechanisms underlying the excavation of new nest chambers in the leaf-cutting ant Acromyrmex lundi. Specifically, we asked whether workers relocate brood and fungus to suitable nest locations, and to what extent the relocated items trigger the excavation of a nest chamber and influence its shape. When brood and fungus were exposed to unfavorable environmental conditions, either low temperatures or low humidity, both were relocated, but ants clearly preferred to relocate the brood first. Workers relocated fungus to places containing brood, demonstrating that subsequent fungus relocation spatially follows the brood deposition. In addition, more ants aggregated at sites containing brood. When presented with a choice between two otherwise identical digging sites, but one containing brood, ants'' excavation activity was higher at this site, and the shape of the excavated cavity was more rounded and chamber-like. The presence of fungus also led to the excavation of rounder shapes, with higher excavation activity at the site that also contained brood. We argue that during colony growth, workers preferentially relocate brood to suitable locations along a tunnel, and that relocated brood spatially guides fungus relocation and leads to increased digging activity around them. We suggest that nest chambers are not excavated in advance, but emerge through a self-organized process resulting from the aggregation of workers and their density-dependent digging behavior around the relocated brood and fungus.     

KATBERGIA GEN. NOV., A NEW TRACE FOSSIL FROM UPPER PERMIAN AND LOWER TRIASSIC ROCKS OF THE KAROO BASIN: IMPLICATIONS FOR PALAEOENVIRONMENTAL CONDITIONS AT THE P/TR EXTINCTION EVENT

Abstract:  A new ichnogenus and ichnospecies of burrow, Katbergia carltonichnus , are described from Upper Permian and Lower Triassic rocks of the Karoo Basin, South Africa, where they are preserved in pedogenically modified overbank deposits that are interpreted as inceptisols subsequently gleysol overprinted. Sigmoidal burrows consist of a long (≥0.5 m) cylindrical tube, ranging from 1–2 cm in diameter, terminating in a slightly larger living chamber. The burrows are unlined and passively filled, preserving a hierarchy of scratch patterns on the burrow walls. Scratch patterns include longitudinal, transverse, and crescent-shaped markings found around the circumference of the burrow, but which are less densely concentrated on the burrow floor. Calcareous concretions are associated with burrowed siltstone intervals, generally restricted to the lowermost decimetre, with nodules nucleating around burrows. Stable δ¹³C and δ¹⁸O isotope data on calcite cement in the burrow fill, entombing siltstone, and associated calcareous nodules all cluster together when plotted, indicating that nodule formation occurred following burrow horizon abandonment and a rise in regional water table. Isotopic data reflect calcite precipitation under a semi-closed system in saturated conditions. A model for burrow emplacement, abandonment and infill, and subsequent cementation by calcite is presented demonstrating that previous interpretations of Late Permian and Early Triassic palaeosol types associated with the P/Tr extinction event must be re-evaluated.     

Two new species of Multiclavula (lichenized basidiomycetes) from savanna soils in Rwanda (East Africa)

Two new species of Multiclavula are described from Rwanda: M. akagerae , with a thallus consisting of turgescent glomerules, and M. rugaramae , with a thallus composed of flattened, rounded, marginate, and dispersed squamules. They grow on soil in frequently burned savannas or on lateritic soils in eastern Rwanda. The genus Lepidostroma should probably be reduced into synonymy with Multiclavula .  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 457–465.     

Burrow Use and the Influence of Ectoparasites in Brants' Whistling Rat Parotomys brantsii

In Brants' whistling rat, Parotomys brantsii, single animals inhabit unusually complex burrow systems containing several nest chambers. We investigated burrow use and examined the effect of ectoparasites on choice of alternative nest chambers by radiotelemetrically monitoring the nocturnal sleeping locations of individual whistling rats, before and after treating them to remove ectoparasites. Prior to treatment, animals used several different nest chambers within a single burrow, moving from one chamber to another every 1.6 d on average, and most individuals also slept in more than one burrow. Anti‐parasite treatment reduced the rate at which animals switched from one nest chamber to another within a burrow. Screening of a separate sample of animals for ectoparasites revealed that they were infested with fleas, mainly Xenopsylla eridos. We suggest that by switching periodically from one nest chamber to another, whistling rats reduce the rate at which ectoparasites, especially fleas, accumulate.     

Ultrastructure and Development of the Ooecial Walls in Some Calloporid Bryozoans (Gymnolaemata: Cheilostomata)

In the brood chambers (ovicells) of six calloporid cheilostomes studied each skeletal wall consists of four calcified layers: (1) a very thin superficial layer of planar spherulitic crystallites, (2) an upper (outer) layer with wall-perpendicular prismatic ultrastructure, (3) an intermediate lamellar layer, and (4) a lower (inner) wall-perpendicular prismatic layer. Comparative studies of both the ovicell wall ultrastructure and early ovicell formation showed a hypothetical opportunity for evolving complex (multilayered) skeletal walls by fusion of the initially separated gymnocystal and cryptocystal calcifications in Cheilostomata. In two species studied, a bilobate pattern in the final stage of the formation of the ooecial roof was encountered in specimens with the cuticle preserved. A possible explanation to this finding is discussed – the bilobate pattern is suggestive of the hypothetical origin of the brood chamber from (1) two flattened spines, or (2) reduction in spine number of an originally multispinous ovicell.     

Reproduction and larval development of Polydora robi (Polychaeta: Spionidae), an obligate commensal of hermit crabs from the Philippines

Abstract. The reproduction of a recently described spionid polychaete, Polydora robi , is examined from the Philippines. Adults inhabit a burrow in the apex of gastropod shells occupied by hermit crabs. Females were found to deposit broods of 18–94 egg capsules in the summer (June–August) and winter months (January–March) sampled. Paired or single egg capsules are attached by stalks to the inside wall of the burrow and contain 40–106 eggs which average 97 μm in diameter. The total number of eggs per brood ranges from 941–8761 eggs and is positively correlated with the total number of segments and length of female worms. Adults of P. robi are polytelic, producing ≤9 successive broods over a 3-month period; a mean of 6.7 d was exhibited between broods in the laboratory. Females utilize sperm stored in the seminal receptacles during successive spawnings. Development occurs within egg capsules until the 3-segment stage, at which time the planktotrophic larvae are released. Juveniles of ∼20 segments are competent to settle on gastropod shells inhabited by hermit crabs. Members of P. robi are relatively fecund, semicontinuous breeders; the life-cycle in this species is similar to the only other known obligate polydorid commensal of hermit crabs.     

Burrow Architecture of the Ghost Crab Ocypode ceratophthalma on a Sandy Shore in Hong Kong

The ghost crab Ocypode ceratophthalma (Pallas) creates burrows of variety shapes at different ages. Juveniles (mean carapace length 11 mm) produced shallow J-shaped burrows, which incline vertically into the substratum (mean depth 160 mm). Larger crabs (17–25 mm carapace length) have Y-shaped and spiral burrows (mean depth 361 mm). These Y-shaped burrows have a primary arm, which extends to the surface forming the opening, and a secondary arm which terminates in a blind spherical ending. The two arms join in a single shaft and end with a chamber at the base. The secondary arms and chambers are believed to be used for mating or as a refuge from predation. The spiral burrows have spiral single channel ending in a chamber. Older crabs (mean carapace length 32.6 mm) had simple, straight single tube burrows, which inclined into the substratum at mean of 73° and had a mean depth of 320 mm. During summer daytime periods, the burrows shelter the crabs from heat and desiccation stress. The sand surface temperature at the burrow opening was ~48 °C but temperatures inside the burrows can drop to 32 °C at a depth of 250 mm. Variation in the burrow architecture with crab age appears to be related to the crab’s behaviour. Juvenile crabs have smaller gill areas and move out of the burrows regularly to renew their respiratory water and, as a result, they do not need a deep burrow. Larger crabs, in contrast, can tolerate prolonged periods without renewing their respiratory water and therefore create deeper and more complex burrows for mating and refuges.     

Nesting and biology of Jucancistrocerus caspicus (hymenoptera,vespidae, eumeninae)

Females of Jucancistrocerus caspicus nest in dense clay ground on the vertical surface of cliffs. The nests contain 1–9 cells (on average 2.8) and have a linear-branched construction. Females surmount the entrance of the burrow with a curved chimney which has a laced structure. The cells are positioned vertically in the main burrow and obliquely or horizontally in the lateral tunnels; the cells in a row are separated with double partitions. The size of the cells is 7–9 × 4–4.5 mm, the diameter of the nest burrow is 4 mm. The egg is laid before provisioning and is attached to the cell ceiling with a filament. Females hunt for weevil larvae and store 23–33 larvae (on average 27.8) in each cell. The species is univoltine, with prepupae hibernating in their cocoons. The nests are parasitized by the cuckoo wasps Chrysis rutilans which cause 11.5% of brood mortality. Adult wasps are killed by the spiders Pholcus sp. living near the nests.     

Burrow morphology and dynamics of mudshrimp in Asian soft shores

Mudshrimps are important soft shore bioturbators but research on the ecology of tropical species has received less attention when compared with their temperate counterparts. The mudshrimp Austinogebia edulis is common on Asian soft shores and lives in burrows for its entire adult life. Epoxy resin casting of A. edulis burrows showed that they were approximately Y-shaped, with an upper U-part and the lower central shaft part. The burrows had two openings extending to the surface; the mean distance between the two openings was 11.0 cm in Hong Kong and 26.4 cm in Taiwan. Openings of the burrows had small chimneys. The tunnels of the burrows were circular, narrow and with a smooth surface (tunnel diameter corresponded to shrimp carapace width). Each burrow was inhabited by a single shrimp and burrows were inter-connected during the mating and reproductive season. Each burrow had four to 12 spherical chambers, which were free of detritus. The chambers were thought to be used for suspension feeding, current generation and as turning points. The depth of burrows was up to 1.1 m. Multivariate analysis on various burrow parameters showed that burrows collected on a mud flat in Taiwan were deeper, had a wider distance between the openings and a larger volume than burrows collected from a sandy shore in Hong Kong, suggesting that burrow architecture is variable between shore types. Burrow architecture, however, did not vary between tidal levels, seasons and shrimp density on the shores in Hong Kong, indicating that the burrows were quite stable within the substratum and were not affected by environmental and biological factors.     

Habitat selection and offspring survival rate in three paracoprid dung beetles: the influence of soil type and soil moisture

Paracoprid dung beetles build brood chambers in the soil beneath a dung pat and provide them with dung Onthophagus species lay one egg into each chamber This paper deals with the influence of soil type and soil moisture on micro-habitat selection and survival of offspring m three middle-European Onthophagus-species ( O coenobita, O fracticonis and O vacca) Discrimination between sandy soils with three different loam contents (0%, 20%, 40%) and four different water contents (4%, 8%, 12%, 16%) was tested in the laboratory During the first 24 h of each replicate beetles which colonized one of the patches did not distinguish between different soil conditions Emigration rates, measured as time when 50% of all individuals had left the patch, and numbers of brood chambers proved to be species specific and depended on soil moisture and soil type Survival rates of the larvae in the brood chambers were influenced nearly exclusively by soil moisture The results are discussed in relation to the ecology of the three species and in context with optimal foraging theories     

Enumerating phytoplankton with an upright compound microscope using a modified settling chamber

A modified settling chamber is described which permits the use of an upright compound microscope for phytoplankton enumerations. The chamber is composed of a 75 × 51 mm rectangular or 70 mm round-glass microslide base with a 130 m thick piece of sheet styrene attached to the upper surface. A circular cell is cut into the styrene material making a 26 mm diameter chamber which is approximately 130–150 m deep. Settling procedures follow Utermöhl's technique, with the use of a 0.13–0.15 mm thick coverslip (50 × 45 mm) to cover the chamber. The overall thickness of the settling slide is 1.13 mm which does not impact on the optical requirements for most objectives, including oil immersion objectives. The chamber encloses a total volume of 69–80 mm³. No statistical differences are observed in cell, filament or colony counts between the new and traditional chambers. Furthermore, count comparisons at different cell concentrations using the new chambers give consistent results. Thus, the resolution and availability of an upright microscope makes the use of the new settling chamber an attractive method for phytoplankton counting, especially in teaching situations.     

First discovery of fossil dung beetle brood balls and nests in the Chadian Pliocene Australopithecine levels

The Pliocene continental formations of the paleo-lake Chad system are known because of the recent discovery of the first australopithecine known west of the Rift Valley. The structures under study are found in sandstone levels associated with a rich fauna, including mammals, birds, reptiles and fishes. Analysis of the depositional environment and fauna indicates a mosaic landscape of gallery forest, savannah, grassland and ephemeral rivers interrupted by lacustrine episodes. This sandstone facies contains bioturbation in the form of sandstone balls 4-12 cm in diameter, slightly flattened at the poles. These structures are characterized by an external husk or crust and by a decimetric cavity in the upper part of the ball. Between the husk and the cavity are a number of concave laminae similar to those of a bulb, whose concavity is directed toward the upper cavity. The comparison between these structures and the brood balls of modern Scarabaeidae shows great similarity, especially in the external husk, the concave internal laminae and the chamber of the grub in the upper part of the structures. This bioturbation is interpreted as fossil brood balls of dung beetles (Coleoptera, Scarabaeidae). Fossil dung beetle brood balls are generally rare, but have been known since the 1940s. They can be very abundant in any series, as described by several authors in South America. The first fossil dung balls were described in this area in 1938 by Frenguelli and by Roselli. These authors describe elementary spherical forms of 35 mm in diameter on average, flattened at the poles and with an upper cavity. The fossil dung beetle brood balls discovered in Chad are the first in which all the internal characteristic structures are preserved. Many of them are connected by a remarkably large net of tunnels which has no parallel in the past or the present.     

Effect of triflumuron on brood development and colony survival of free-flying honeybee, Apis mellifera L.

Abstract:  The effect of the insect growth regulator (IGR) triflumuron (Alsystin^® 25 WP) on honeybee, Apis mellifera L. (Hym., Apidae), was studied in a semi-field test. Free-living colonies were fed one litre per hive of sucrose syrup containing 0, 0.025, 0.25 or 2.5 g of triflumuron. A significant reduction in flight activity was noted 6–10 weeks post-treatment at the two higher doses. These colonies reared less brood than before treatment. While the comb area occupied by uncapped brood was as high as [0.025 and 0.25 g active ingredient (a.i.)] or higher (2.5 g a.i.) than before treatment, there was a significant decline in capped brood at the two higher doses, indicating enhanced larval mortality. No capped brood was reared in the hive treated at the highest dose from 3–9 weeks post-treatment. Yet there was a significant accumulation of pollen and honey in the brood compartment at all doses. All colonies except the one treated at the highest dose survived the following winter. However, at 43 weeks post-treatment, hives treated at intermediate and low doses showed a significant increase in uncapped brood and a significant decrease in capped brood. This study revealed a strong residual toxicity of triflumuron to brood and substantiated its classification as hazardous to honeybee.     

Early Colony Development in Aetea (Bryozoa)

External structures on the erect parts of zooids of Aetea havebeen demonstrated to be brood chambers by observation of release,settlement and metamorphosis of larvae from the chambers. Theancestrula is smaller than, but very similar to succeeding zooidsin the primary zone of astogenetic change, which do not showtubular connections. Sections through brood chambers and zooidsshow that part of the brood chamber wall may be slightly calcified.Brood chambers appear to be products of the external zooid walland not diverticula derived from the tentacle sheath.     

Reproduction of spined loach, Cobitis taenia, (Cypriniformes; Cobitidae) under laboratory conditions

A simple and reliable method is described for breeding spined loach, Cobitis taenia Linnaeus, 1758, under laboratory conditions. Three 40 L aquaria were each provided with a thick tuft of moss placed on top of a gauze-covered plastic box to serve as a spawning site. Ovoposition always occurred in the most densely available vegetation. The nonadhesive eggs fell through the gauze into the box. The spined loach is a fractional spawner releasing eggs in 14–18 batches at intervals of 2–23 (median 6) days. The total number of eggs per female was 2905–4282 during the reproductive season of 101–120 days. Yolks measured 1.14 ± 0.07 mm and eggs were 2.54 ± 0.22 mm in diameter. Total larval length was 5.03 ± 0.34 mm at hatching and 6.77 ± 0.34 mm at the beginning of exogenous feeding. The method allowed the rearing of numerous young for conservation measures and experimental investigations.