Reconstruction of fig wasp mating structure: how many mothers share a fig?

Abstract.  1. Fig wasps (Hymenoptera: Agaonidae) represent an important model system for studies of sex ratio evolution, mainly because they may adjust their sex ratios in response to the numbers of ovipositing females (foundresses) that enter a fig and their clutch size.
2. Until recently, it was assumed that all foundresses fail to re-emerge from the figs that they have entered to oviposit, but there is increasing evidence that such re-emergence may be routine. The common practice of counting the number of dead foundresses present in a fig in order to deduce the number of foundresses is therefore questionable in species where failure to re-emerge has not been confirmed.
3. In this study, the alternative approach of microsatellite markers was used to reconstruct the within-fig breeding structure of a pollinating fig wasp by genetic analysis of the offspring. Broods of Liporrhopalum tentacularis , a species where foundresses regularly re-emerge from figs, were collected from figs of Ficus montana in their natural habitat in Indonesia as well as from an experimental glasshouse population in Leeds (U.K.).
4. The estimated foundress densities in the glasshouse population were similar to those in the field and ranged from one to six foundresses per brood.
5. Nearly 40% of all broods were produced by a single foundress, indicating that mating in these broods occurs exclusively between full siblings. High levels of inbreeding are therefore common in this species.     

Body size and social dominance influence breeding dispersal in male Pachydiplax longipennis (Odonata)

1. Dispersal behaviour can be affected by an individual's phenotype, by the environmental or social context they experience, and by interactions between these factors. Differential dispersal propensities between individuals may also be an important modifier of functional connectivity between populations. To assess how a key trait, body size, affected both social interactions and dispersal behaviour, this study examined the relationship between body size, antagonistic interactions, and breeding dispersal in male dragonflies (Pachydiplax longipennis) across a seasonal decline in adult body size. 2. During a seasonal peak in male body size in this study, dispersers were smaller than non‐dispersers. Later in the season, the body size of dispersers and non‐dispersers did not differ. 3. Focal observations found that body size was related to competitive dominance, large males engaged in aggressive chases more often and smaller males were more frequently pursued. 4. These results indicate that when large males were present, small males were more likely to disperse suggesting that dispersal is a tactic adopted by social subordinates in this context. If breeding dispersal is typically undertaken by subordinate males, functional connectivity between populations may be less than estimated from absolute dispersal rates.     

Vibration‐mediated territoriality in the warty birch caterpillar Drepana bilineata

Abstract The warty birch caterpillar Drepana bilineata produces two distinct types of vibrational signals (mandible drumming and anal scraping) during interactions with conspecifics. Vibrational signalling is characterized using standard and high‐speed videography synchronized with laser‐doppler vibrometry, and behavioural experiments test the hypothesis that signalling functions to advertise occupancy of birch (Betula) leaves. Drumming involves raising the head and striking the leaf with the sharp edges of the open mandibles. Anal scraping involves dragging a pair of specialized oar‐shaped setae against the leaf surface. Staged encounters between leaf residents and conspecific intruders result in the resident signalling, with rates increasing as the intruder moves closer. Intruders signal significantly less often than residents. Conflicts are typically resolved within a few minutes, with the resident winning in 61% of the trials, and the intruder winning in 6%. Contests that last more than 30 min are deemed ‘ties’ and comprise the remaining 33% of trials. The results support the hypothesis that vibrational signals function to advertise leaf occupancy. Vibrational communication is believed to be widespread in Drepanoidea caterpillars, but has only been described in two species to date: D. bilineata (present study) and Drepana arcuata. It is proposed that differences in territorial behaviour and signalling between these species are related to their relative investments in silk leaf mats and shelters. The proximate and ultimate bases for the evolution of vibrational communication in caterpillars are discussed.     

Performance of Spread Spectrum Global Positioning System Collars on Grizzly and Black Bears

ABSTRACT Global Positioning System (GPS) telemetry is a prevalent tool now used in the study of large mammals. Global Positioning Systems either store the data on board the collar or contain a remote-transfer system that allows for data recovery at more frequent intervals. Spread spectrum (S-S) technology is a new mode of data transfer designed to overcome interference problems associated with narrow-band very high frequency and ultra high frequency data-transfer systems. We evaluated performance of S-S GPS radiocollars deployed on grizzly (Ursus arctos) and black bears (U. americanus). We also evaluated variables that influenced GPS fix success rates, with particular focus on animal activity, time of year, and temperature. The S-S GPS collars performed to our expectations and met study objectives; we did not experience any major problems with the data-transfer system. We observed varying rates of fix success that were directly related to recorded activity counts. Using logistic regression, we verified that activity counts were a reasonable measure of resting or feeding-traveling in both bear species. Our results showed that 73% and 79% of missed fixes, respectively, occurred when we predicted black and grizzly bears to be resting. Temperatures measured in the canister of the collar were not correlated with air temperature, suggesting posture and activity influenced canister temperature. Both measures of temperature were predictive of fix success. We did not find that fix success was related to body morphology (i.e., neck circumference, mass, and chest girth), fix interval, position of the GPS antenna relative to the sky, or sex of the bear. We conclude that fix success for both species is strongly related to activity patterns and time of year. Activity counters appear to be a reasonable measure of this behavior, and we recommend researchers consider including an activity-count system when deploying GPS collars. We also recommend researchers explore building separate models of habitat selection based upon categories of activity to account for bias in fix success associated with bear behavior.     

Microsatellite loci for studies of wild and hatchery Australian Murray cod Maccullochella peelii peelii (Percichthyidae)

Murray cod is a species of conservation concern that is subject both to wild harvest and to aquaculture production. Six polymorphic microsatellite loci have been developed for this species, which will facilitate studies of wild‐stock structure, will help the management of hatchery diversity, and will aid genetic improvement programmes. The markers exhibited nonindependence of genotypes between loci and deviations from Hardy–Weinberg expectations, although these most probably reflect practices at the hatchery from which the genotyped individuals were sourced.     

Spatial Ecology of a Canada Lynx Population in Northern Maine

Abstract Canada lynx (Lynx canadensis) were listed as a federally threatened species in 14 states at the southern extent of their geographic range in March 2000, with Maine being the only state in the northeastern United States known to support a resident population. Relatively little information is known about the ecology of lynx living at the southern edge of their range, including range requirements, movements, and spatial organization. Basic knowledge of lynx ecology is needed for federal recovery planning efforts. Between 1999 and 2004, we trapped and radiocollared 43 lynx (21 M, 22 F) in northern Maine in an intensively managed and predominantly early successional forested landscape. We estimated diurnal annual and seasonal home-range size for male and female lynx using the 85% fixed-kernel home-range estimator. Annual home ranges of adult male lynx (x̄ = 53.6 km²) were more than twice the size of adult female home ranges (x̄ = 25.7 km²). Home ranges of adult females during snow periods (x̄ = 38.3 km²) were nearly 3 times larger than their snow-free-period ranges (x̄ = 14.3 km²), whereas, snow-free ranges of adult males (x̄ = 58.8 km²) were slightly larger than their snow-period ranges (x̄ = 45.2 km²). We observed a limited amount of home-range overlap among lynx of the same sex (F: x̄ = 17.2%; M: x̄ = 11.8%). Lynx of opposite sex showed more extensive overlap (x̄ = 24.3%). Most home-range shifts of resident lynx were typically not extensive. Based on territory mapping, we estimated a minimum lynx density of 9.2–13.0 lynx/100 km². We observed lynx spatial ecology and densities that were more similar to northern lynx populations when hares were abundant than to other southern lynx populations, suggesting that region-specific studies under varying habitat conditions and hare densities are needed to ensure realistic recovery goals and effective management of lynx at the southern extent of their range.     

Adaptation to host plants may prevent rapid insect responses to climate change

We must consider the role of multitrophic interactions when examining species' responses to climate change. Many plant species, particularly trees, are limited in their ability to shift their geographic ranges quickly under climate change. Consequently, for herbivorous insects, geographic mosaics of host plant specialization could prohibit range shifts and adaptation when insects become separated from suitable host plants. In this study, we examined larval growth and survival of an oak specialist butterfly (Erynnis propertius) on different oaks (Quercus spp.) that occur across its range to determine if individuals can switch host plants if they move into new areas under climate change. Individuals from Oregon and northern California, USA that feed on Q. garryana and Q. kelloggii in the field experienced increased mortality on Q. agrifolia, a southern species with low nutrient content. In contrast, populations from southern California that normally feed on Q. agrifolia performed well on Q. agrifolia and Q. garryana and poorly on the northern, high elevation Q. kelloggii. Therefore, colonization of southern E. propertius in higher elevations and some northern locales may be prohibited under climate change but latitudinal shifts to Q. garryana may be possible. Where shifts are precluded due to maladaptation to hosts, populations may not accrue warm‐adapted genotypes. Our study suggests that, when interacting species experience asynchronous range shifts, historical local adaptation may preclude populations from colonizing new locales under climate change.     

Testing Global Positioning System Telemetry to Study Wolf Predation on Deer Fawns

ABSTRACT We conducted a pilot study to test the usefulness of Global Positioning System (GPS) collars for investigating wolf (Canis lupus) predation on white-tailed deer (Odocoileus virginianus) fawns. Using GPS collars with short location-attempt intervals on 5 wolves and 5 deer during summers 2002–2004 in northeastern Minnesota, USA, demonstrated how this approach could provide new insights into wolf hunting behavior of fawns. For example, a wolf traveled ≥1.5–3.0 km and spent 20–22 hours in the immediate vicinity of known fawn kill sites and ≥0.7 km and 8.3 hours at scavenging sites. Wolf travel paths indicated that wolves intentionally traveled into deer summer ranges, traveled ≥0.7–4.2 km in such ranges, and spent <1–22 hours per visit. Each pair of 3 GPS-collared wolf pack members were located together for ≤6% of potential locations. From GPS collar data, we estimated that each deer summer range in a pack territory containing 5 wolves ≥1 year old and hunting individually would be visited by a wolf on average every 3–5 days. This approach holds great potential for investigating summer hunting behavior of wolves in areas where direct observation is impractical or impossible.     

The Taphonomy of Disaster and the (Re)Formation of New Orleans

Using observations from recent participation in post-Katrina recovery efforts in New Orleans, I make the case in this article that taphonomic processes such as trash removal, deposition, earthmoving, and demolition are a primary medium through which individuals and communities reconstitute themselves following a disaster. Taphonomy, or the formation of the archaeological record, does not simply reflect social processes, it is a social process. The taphonomic processes currently underway through the clean-up and rebuilding efforts in New Orleans dramatically illustrate this point. I recommend that both ethnographers and archaeologists undertake a fine-grained ethnoarchaeology of disaster. I engage with the literature of disaster to illustrate the potentials I see for this type of study, particularly as it pertains to the culture–nature nexus, perceptions of vulnerability, and the revelatory power of disasters.