2000. Dr. Pangloss restrained by the Red Queen -steps towards a unified defence theory. -Oikos 89: 267 -274.Animals and plants defend themselves against a variable community of biological enemies. We argue that the effectiveness of allocation to defence (the success of defence per unit allocation) may be expected to decrease as the diversity of attack types increases, and asked how the optimal allocation to defence covaries with the effectiveness of defence. Variation in effectiveness links optimal defence to coevolutionary processes; the prime characteristic of coevolutionary interactions is that they promote and maintain genetic variation in both hosts and their enemies, leading to variation in the effectiveness of defence. We present a simple model suggesting that as effectiveness decreases, the fitness benefit of defence disappears. In other words, when effectiveness is low, the optimal strategy is to tolerate damage. As effectiveness increases, the optimal allocation flips rapidly from no-defence (tolerance) to high allocation to defence, and then decreases at a decelerating pace as effectiveness increases. We conclude that diversifying coevolution, as it covaries with the effectiveness of defence, constrains the evolution of optimal defence strategies and may be a very important component in determining the optimal allocation to defence and variation in the success of defence as it is seen in the wild.

Organisms are often confronted by both predators and pathogens. Defending against such widely divergent enemies requires more than one type of defence. Multiple defences, however, raise the possibility of trade-o¡s among defences. We tested for such trade-o¡s by manipulating the level of predator-avoidance behaviour and immune function in the freshwater snail Lymnaea stagnalis (Gastropoda: Pulmonata). Our results show that predator avoidance and immune function had clear costs in terms of reproduction and survival. Further, we show that increased levels of predator-avoidance behaviour reduced the snails' ability to defend against potential pathogens. Predator-avoidance behaviour may thus have the additional indirect cost of reduced immunocompetence and increased susceptibility to pathogens. Our results suggest that ecological factors (e.g. predator density) may considerably modify the expression and costs of immune defences.

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Ecological factors may influence the number of parasites encountered and, thus, parasite species richness. These factors include diet, gregarity, conspecific and total host density, habitat, body size, vagility, and migration. One means of examining the influence of these factors on parasite species richness is through a comparative analysis of the parasites of different, but related, host species. In contrast to most comparative studies of parasite species richness of fish, which have been conducted by using data from the literature, the present study uses data obtained by the investigators. Coral reef fishes vary widely in the above ecological factors and are frequently parasitized by a diverse array of parasites. We, therefore, chose to investigate how the above ecological factors influence parasite species richness in coral reef fishes. We investigated the endoparasite species richness of 21 species of butterfly fishes (Chaetodontidae) of New Caledonia. We mapped the diet characters on the existing butterfly fish phylogeny and found that omnivory appears to be ancestral. We also mapped the estimated endoparasite species richness, coded from low to high parasite species richness, on the existing butterfly fish phylogeny and found that low parasite species richness appears to be associated with the ancestral state of omnivory. Different dietary and social strategies appear to have evolved more than once, with the exception of obligate coralivory, which appears to have evolved only once. Finally, after controlling for phylogenetic relationships, we found that only the percentage of plankton in the diet and conspecific host density were positively correlated with endoparasite species richness.

A time-variable one-dimensional model (called ViM for Vapor Intrusion Model)to predict indoor vapor concentrations in a dwelling with a combined basement and crawl space has been developed. ViM predicts vapor concentrations in each of the three compartments. Volatile chemicals that intrude into the dwelling are assumed to originate from soil, groundwater (where an attenuating plume is simulated), or ambient air. Processes included in the model are advection, diffusion, biodecay, and adsorption in the soil column; transport by diffusion and advection into individual crawl space and basement compartments; advection from each compartment into an overlying dwelling space; and exchange of ambient air and indoor air. The time-variable concentration fields are solved by first transforming the partial and ordinary differential equations into Laplace space, solving the resulting ordinary differential equations or algebraic equations, and numerically inverting those equations. This approach was an expedient way of handling the coupling between the subsurface and the dwelling. ViM was applied to a building (Building 20) located at the former Moffett Field Naval Air Station, in Mountain View, CA. The building is a former bachelor officer's quarters. The shallow groundwater beneath the building is contaminated with a number of volatile chemicals, including trichloroethene, cis-1,2-dichloroethene, and trans-1,2-dichloroethene, all of which were simulated. Using indoor air data collected in 2003-2004, and other field data collected prior to that time, the accuracy of the model's predictions was demonstrated. ViM's results were also compared against a version of the steady-state Johnson and Ettinger model (1) that was modified to accommodate a dwelling with a combined crawl space and basement (called the JEM model in this paper). The predictions from the JEM model were consistently higher than the predictions from ViM, but still near the upper range of the observed data.

Efforts to limit the impact of invasive species are frustrated by the cryptogenic status of a large proportion of those species. Half a century ago, the state of Hawai'i introduced the Bluestripe Snapper, Lutjanus kasmira, to O'ahu for fisheries enhancement. Today, this species shares an intestinal nematode parasite, Spirocamallanus istiblenni, with native Hawaiian fishes, raising the possibility that the introduced fish carried a parasite that has since spread to naïve local hosts. Here, we employ a multidisciplinary approach, combining molecular, historical, and ecological data to confirm the alien status of S. istiblenni in Hawai'i. Using molecular sequence data we show that S. istiblenni from Hawai'i are genetically affiliated with source populations in French Polynesia, and not parasites at a geographically intermediate location in the Line Islands. S. istiblenni from Hawai'i are a genetic subset of the more diverse source populations, indicating a bottleneck at introduction. Ecological surveys indicate that the parasite has found suitable intermediate hosts in Hawai'i, which are required for the completion of its life cycle, and that the parasite is twice as prevalent in Hawaiian Bluestripe Snappers as in source populations. While the introduced snapper has spread across the entire 2600 km archipelago to Kure Atoll, the introduced parasite has spread only half that distance. However, the parasite faces no apparent impediments to invading the entire archipelago, with unknown implications for naïve indigenous Hawaiian fishes and the protected Papahānaumokuākea Marine National Monument.

Abstract. Two new, one known and three unidentified species of the nematode family Camallanidae are reported and described from the intestines of marine perciform fishes off the southwestern coast of New Caledonia, South Pacific: Camallanus carangis Olsen, 1952 from the forked-tailed threadfin bream Nemipterus furcosus (Nemipteridae), the yellowstriped goatfish Upeneus vittatus and the whitesaddle goatfish Parupeneus ciliatus (both Mullidae) (new host records); Procamallanus (Spirocamallanus) variolae sp. n. from the white-edged lyretail Variola albimarginata (type host) and the blacktip grouper Epinephelus fasciatus (both Serranidae); Procamallanus (Spirocamallanus) longus sp. n. from the twotone tang Zebrasoma scopas (Acanthuridae); Procamallanus (Spirocamallanus) sp. 1 (female tail with 2 terminal spikes on a digit-like projection) from the speckled sandperch Parapercis hexophtalma (Pinguipedidae); Procamallanus (Spirocamallanus) sp. 2 (female tail with 1 spike on a digit-like projection) from the drab emperor Lethrinus ravus (Lethrinidae) and Procamallanus (Spirocamallanus) sp. 3 (female tail with a smooth digit-like protrusion) from the two-lined monocle bream Scolopsis bilineata (Nemipteridae). Camallanus paracarangis Velasquez, 1980 is synonymized with C. carangis. Several additional species of Camallanus from marine fish of the Indo-Pacific region may be synonymous with C. carangis as it has a poorly sclerotized left spicule and 3 small caudal projections on the tail of young (i.e., non-gravid) females. The fourth-stage larva of C. carangis is described for the first time. P. (S.) variolae differs from most similar species of this region mainly in the position (i.e., at level or posterior to the nerve ring) and shape of deirids. P. (S.) longus differs from the similar P. (S.) chaimha mainly in a different arrangement of postanal papillae, shape of the female tail, much longer right spicule (429 µm) and longer body of gravid females (38-55 mm). All Camallanus and Procamallanus (Spirocamallanus) spp. reported here represent the first records of camallanids from marine fishes in New Caledonian waters.

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