Rank and colony defense against conspecifics in a facultatively eusocial hover wasp

An important benefit of social living is increased capacityfor defense. Highly eusocial species have often evolved a fightingcaste for this purpose, but many facultatively eusocial insectsand cooperatively breeding vertebrates lack morphological castesand the decision to defend or not can depend on costs and benefitsto each individual. Defense by subordinates in a social groupcan be regarded as a form of helping, and helping input oftenvaries among subordinates of different age or size. Severalhypotheses attempt to explain variation in helping effort, includingthe effects of relatedness and differences in the costs of helping.Evidence for these hypotheses is mixed and often lacks dataon the rank of subordinates, an important determinant of expectedfuture fitness. We examined individual variation in propensityto defend the nest against conspecifics in the tropical hairy-facedhover wasp Liostenogaster flavolineata. Prior to experimentation,we determined the positions of all wasps in the age-based queueto inherit the single egg-laying position in each L. flavolineatagroup. Two approaches were then used: observations of defenseagainst natural intrusions by conspecifics and experimentaltrials where wasps were presented attached to a wire. Higherranks were more likely to defend the nest than lower ranks,opposite to the pattern previously documented for another formof helping: foraging effort. Possible explanations for thisresult are that higher ranked females are better defenders andthat they suffer a larger decrease in expected future fitnesswhen an intruder usurps their position in the inheritance queue.     

Bathyal ostracodes from the Florida-Hatteras slope,the Straits of Florida,and the Blake Plateau

Epibathyal ostracodes from the Florida-Hatteras slope, the Blake Plateau and the Straits of Florida were studied to determine the relationship of numerous genera and species to bottom-water environmental conditions such as dissolved oxygen and bottom-water temperatures. From a total of 100 samples, 44 samples evenly distributed between 200 and 1100 m water depth and having an average of 325 specimens were examined in detail.Using occurrence data from the adjacent continental shelf, carapace preservation, Rose Bengal staining and population data, indigenous death assemblages were distinguished from transported or reworked fossil specimens. The percent of transported specimens varied as follows: Blake Plateau < 1%; Straits of Florida 10–60%; Florida-Hatteras slope 1–15%. Indigenous death assemblages contained between 10 and 61 species per sample, averaging 33.3 species.Krithe, Argilloecia andPseudocythere occur in > 90% of the samples and usually constitute 10 to 30% of each.Trachyleberidea, Bairdoppilata, Saida, Paranesidea, Ambocythere, Bythocypris, Cytherella, Bradleya, Henryhowella, and Polycopidae occur in 45 to 80% of the samples in varying percentages.The upper depth limits of 39 taxa occur at or just below the thermocline suggesting a relationship to temperature.Australoecia, Quasibuntonia, Cytheropteron, Ruggieriella, Saida, Ambocythere, Trachyleberidea, Macrocypris, Krithe, “Thalassocythere”, andCytherella are most common or restricted to the O₂ minimum zone. Conversely,Anchistrocheles, Bradleya, Henryhowella, andRockallia are most common below 750 m in well oxygenated water with temperatures below 8°C.The results show that: (1) ostracodes display a narrow depth zonation controlled by dissolved oxygen and water temperature; (2) species diversity is very high for a bathyal zone; (3) ostracodes can be used to identify the source of sediment that has been transported downslope; and (4) some taxa are useful in recognizing low oxygenated water in Cenozoic deposits.     

Temporal variation in herbivore host-plant preference and performance: constraints on host-plant adaptation

Temporal variation in the acceptability or suitability of plant genotypes to an herbivore has seldom been considered as a possible constraint limiting the adaptation of herbivores to particular plant genotypes, or the occurrence of a positive correlation between host-plant preference and offspring performance. In this study, we used data spanning 12 yr from the same 20 clones of goldenrod ( Solidago altissima ) to examine the temporal variation in oviposition preference and offspring performance of a stem-galling fly, Eurosta solidaginis . We found that the stem galler's preference for, or performance on, the different clones was uncorrelated between years of this study. Furthermore, we found that the relative rankings of clones changed by an average of 31% between successive years. We suggest that these consistently high year-to-year fluctuations in preference and performance by E. solidaginis are likely due to environmental factors (e.g., water and nutrient levels, or abundance of interspecific herbivores) that fluctuate over time and are known to differentially affect the acceptability and suitability of clones to herbivores; i.e., genotype×environment interactions. These results are significant because temporal fluctuations in host-plant preference and performance are likely to favor a more generalized diet by herbivorous insects.     

Nipple reconstruction: the S flap

A one-stage procedure to reconstruct the nipple-areola complex is presented, with special attention given to nipple volume and projection using local dermis-fat flaps. The preliminary results have been very encouraging.     

Aerial surveying of grey seal breeding colonies on the Blasket Islands, Co. Kerry, the Inishkea Group, Co. Mayo and the Donegal Coast, Ireland

The status of Ireland's grey seal population and its relationship with that of Britain and Western Europe, are poorly understood. The existing population estimate for grey seals in Ireland is outdated and urgency exists to establish a reliable national population estimate for this species, listed as an Annex II species under the EU Habitats Directive. Prior to the initiation of a survey on a national scale, the success or otherwise of aerial techniques in surveying grey seal breeding habitat on the Irish coastline first needs to be established. Previously, surveys were boat-based and were susceptible to adverse weather conditions frequently encountered during the autumn breeding season. The feasibility of using aerial techniques to survey grey seal breeding colonies in Ireland was tested during the breeding season of 2003.