Mutualism or opportunism? Tree fuchsia (Fuchsia excorticata) and tree weta (Hemideina) interactions

Mutualisms or interspecific interactions involving net mutual benefits, are an important component of ecological theory, although effectively demonstrating mutualism is notoriously difficult. Among two New Zealand endemics, a slightly elevated germination rate of Fuchsia excorticata (Onagraceae) seeds after passage through tree weta (Orthoptera: Anostostomatidae) compared with seeds manually extracted from fruit, led to the proposal that a mutualistic relationship exists between this plant and animal. An improved germination rate, or any other single trait, however, does not alone constitute evidence for mutualism; the relative costs and benefits of numerous components of the interaction need to be accounted for. We considered the costs and benefits to F. excorticata of the putative seed dispersal mutualism with tree weta. Tree weta provided with F. excorticata fruits destroyed 78% of the seeds they consumed, did not move fruit; and faeces containing seeds were deposited near their roost holes (which are naturally in trees). The seeds remaining after fruit consumption and those that are ingested but survive gut passage are unlikely to be deposited in suitable habitat for seedling survival. Plant food preferences of captive tree weta assessed using pairwise leaf choice tests showed that the leaves of F. excorticata were the least preferred of six commonly encountered plants. In addition, we found that tree weta did not show a preference for F. excorticata fruit over a standard leafy diet, indicating they are unlikely to be actively seeking fruit in preference to other sources of food. These observations indicate that any interaction between tree weta and F. excorticata is likely to be opportunistic rather than mutualistic, and highlight the difficulty of characterizing such interactions.     

Isospora peromysci Davis, 1967 (Apicomplexa: Eimeriidae) in Peromyscus leucopus and P. maniculatus (Rodentia: Cricetidae) from Texas

Oocysts of Isospora peromysci (Davis, 1967) (Apicomplexa: Eimeriidae) were recovered from the feces of 1/30 (3.3%) white-footed mice, Peromyscus leucopus , in Johnson County, Texas. This report represents a new host and geographic record for the parasite. The coccidium was also found in 1/20 (5.0%) deer mice, P. maniculatus , from the same locale. Morphological data are provided on the sporulated oocyst of I. peromysci and comparisons are made with previously published information on the species from other geographic localities.     

Characterization of 15 single nucleotide polymorphism markers for chimpanzees (Pan troglodytes)

We report the characterization of 15 new single nucleotide polymorphism markers for a threatened species, the chimpanzee (Pan troglodytes), developed using a targeted gene approach. These markers are derived from the Y chromosome and autosomal regions of the genome and show frequency differences between chimpanzee subspecies from central and western Africa. These single nucleotide polymorphism markers are the first to be designed for the genotyping of wild chimpanzee populations and will provide a useful addition to the genetic tools employed for the conservation management of this threatened species.     

Does Confirmed Pathogen Transfer between Sanctuary Workers and Great Apes Mean that Reintroduction Should not Occur?

This commentary discusses the findings and conclusions of the paper “Drug resistant human Staphylococcus aureus findings in sanctuary apes and its threat to wild ape populations.” This paper confirms the zoonotic transfer of Staphylococcus aureus in a sanctuary setting. The assertion that this in itself is enough to reconsider the conservation potential of ape reintroduction provides an opportunity to discuss risk analysis of pathogen transmission, following IUCN guidelines, using S. aureus as an example. It is concluded that ape reintroduction projects must have disease risk mitigation strategies that include effective biosecurity protocols and pathogen surveillance. These strategies will assist with creating a well planned and executed reintroduction. This provides one way to enforce habitat protection, to minimise human encroachment and the risks from the illegal wildlife trade. Thus reintroduction must remain a useful tool in the conservation toolbox. Am. J. Primatol. 74:1076‐1083, 2012. © 2012 Wiley Periodicals, Inc.     

Phenology of Stomoxyinae in a Kenyan forest

Abstract. The biology of nineteen taxa of African Stomoxyinae was studied during experiments with odour-baited Vavoua traps in Nairobi National Park, Kenya. Both male and female Stomoxys were captured in similar numbers with C0₂ released at 2 1/min or octenol released at 2 mg/h. Some species of Haematobosca reacted synergistically to a combination of these two attractants, producing large increases in catch. Stygeromyia and Rhinomusca responded only to C0₂, and Prostomoxys did not respond to either bait. Many different activity patterns were documented in these genera, but most activity was concentrated just prior to sunset. For example, at peak densities nearly 1500 Stomoxyinae representing fourteen taxa were caught in a single trap between 18.00 and 19.00 hours. The Stomoxyinae community was exceptionally diverse when compared with other biting fly communities. Using data from traps set with different odour baits in the park forest, Shannon-Wiener diversity indices (H') varied from 2.5 to 2.8, and evenness (J') varied between 0.61 and 0.68. The Stomoxys population was extremely female-biased at the start of the rainy season, with species such as S.inornatus and S.boueti consisting of nearly 100% females. Sex ratios equalized when the first rainy-season generation emerged. Population doubling times estimated from trap indices were approximately 12–16 days in two habitats (forest and riverine woodland).     

Mating or ovipositing? A crucial decision in the life history of the cabbage aphid parasitoid Diaeretiella rapae (M’Intosh)

1. The reproductive fitness of a parasitoid depends on its mating and ovipositing success. Virgin haplodiploid females can reproduce, but produce only males, and may diminish fitness by producing more male offspring than required. Therefore, females must decide on whether to mate or oviposit first. 2. This study was conducted to assess the mating versus ovipositing decision and its impact on the reproductive fitness of Diaeretiella rapae (Hymenoptera: Aphididae), an endoparasitoid of the cabbage aphid Brevicoryne brassicae (Hemiptera: Aphididae). 3. When newly emerged females were given a choice between mating and ovipositing, about 62% of D. rapae females preferred to mate before ovipositing. Those females who oviposited before mating parasitised only 10% of the available aphids. After mating, females superparasitised their hosts with fertilised eggs, which resulted in a highly female‐biased sex ratio in the offspring. 4. Mating success was very high (91%) in the presence of hosts (cabbage aphid nymphs) compared with that in the absence of aphids. However, mating success was not influenced by the quality (size) of the hosts present in the mating arena, despite a parasitoid preference for larger hosts during oviposition. The time between pairing and mating was also shorter in the presence of host aphids. The mean number of aphids parasitised and the parasitism rate were significantly greater after mating.