In Chile, loxoscelism is caused by the bite of the Loxosceles laeta spider. The clinical presentation has two different forms: cutaneous loxoscelism (CL) and vicero-cutaneous loxoscelism, which is less frequent. Cutaneous loxoscelism includes an uncommon clinical variation (4%), called CL with edematous predominance (CLEP). We present a 5-year-old patient with sudden pain and edema on his right eyelid associated with fever, which progressed rapidly involving the right hemifacial area, frontal region, and left eyelid. Angioedema and pre-orbital cellulitis were discarded and CLEP was suspect. Cutaneous loxoscelism with an edematous predominance is self-limited, benign and with little or no necrotic injury due to the edema, which dilutes the toxin-induced enzymatic process causing necrosis. As in the reported cases it usually responds well to medical treatment and does not cause visceral involvement.

Positive interactions between species may change in outcome over time and may differ for the two interacting species. We explored the seasonal patterns of facilitation between an ascidian (Styela clava) and a macroalga (Undaria pinnatifida) by following their association for a complete sporophytic phase. In addition, we investigated how the relationship affected the morphometric parameters of U. pinnatifida, and whether the association had a negative outcome for S. clava. We performed monthly surveys in San Antonio Bay (Argentina) for nearly 1 yr to evaluate U. pinnatifida density (both the total and mature individuals exclusively) on different substrates to determine whether U. pinnatifida was more closely associated with S. clava than with inert substrates (i.e. consolidated and nonconsolidated). Moreover, we compared the morphometry of U. pinnatifida between substrates (S. clava vs. rock) and collected S. clava individuals overgrown by U. pinnatifida and classified them by their holdfast coverage to assess their condition (dead or alive). A higher total density of U. pinnatifida was associated with S. clava than with other substrates from autumn to spring. U. pinnatifida individuals growing on S. clava were smaller than those growing on rock. Finally, the probability of S. clava dying increased for individuals with higher holdfast coverage, although the scarcity of dead individuals found suggested a negligible influence. Our findings indicate that whereas U. pinnatifida clearly benefitted from this interaction by appearing earlier in the field and presenting higher densities that could benefit the population when associated with S. clava, for S. clava the relationship appeared more neutral.

Coastal salt marshes provide important habitat for fishes and crustaceans, including species of commercial value that feed or take refuge in the marsh. Yet population abundances vary considerably between sites, often without clear explanation. We hypothesised that faunal abundance and mean size would be positively related to 2 physical properties that govern marsh accessibility to water-dependent species, as has been found on the southeastern coast of the USA: (1) the volume of water exchanged by tidal flooding, which gives access to the marsh, and (2) edge amount, the length of the water-vegetation borderline per unit area where species can take refuge and feed. Digital terrain models and tidal information were used to select 5 marshes in Wales, UK, that differed in edge amount and water exchange (52°N, 4°W). Fishes and crustaceans were sampled using baited traps, fyke nets and seine nets. In total, 15 species were caught, including commercially valuable brown shrimp, European eel and sea bass. We found water exchange volume, but not edge amount, boosted fish and crustacean abundances. Crab and sea bass sizes were both negatively affected by water exchange, while shrimp and fish sizes were unaffected. Our findings show how the mechanisms that drive fish and crustacean abundances and sizes vary between geographical regions. Feasibly, fisheries associations with marsh hydrogeomorphology might operate differently as well.

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