Habituation in Aedes aegypti mosquito larvae is context specific.

Mosquito larvae live in water and perform a stereotyped escape response when a moving object projects its shadow on the water surface, indicating potential risk of predation. Repeated presentations of the shadow induce a decrease in the response as a result of habituation, a form of non-associative learning defined as the progressive and reversible decrease in response to a specific reiterative innocuous stimulus. Nevertheless, habituation can be context specific, which indicates an association between the context and the stimulus. The aim of this work was to study context specificity in habituation in mosquito larvae Aedes aegypti. Larvae were individually placed in Petri dishes positioned over black, white or black-white striped cardboard as background (visual context). Larvae were presented with a shadow produced by a cardboard square (training) over the course of 15 trials. After the 15th trial, the background was changed and the stimulus was presented once again (test). To analyse habituation in different contexts, we developed a series of learning curve models. We performed a Bayesian model selection procedure using those models and the data from the experiments to find which model best described the results. The selected model was a power law learning curve with six parameters (habituation rate; context-specific asymptotic habituation response, with one parameter per context, i.e. 3 parameters in total; response increase; and autocorrelation) describing the whole experimental setup with a generalised r2 of 0.96. According to the model, a single habituation rate would indicate that habituation was independent of the context, whilst asymptotic habituation would be context specific. If the background was changed after training, there was an increase in response in the test, evincing context specificity in habituation.

Influence of competition and intraguild predation between two candidate biocontrol parasitoids on their potential impact against Harrisia cactus mealybug, Hypogeococcus sp. (Hemiptera: Pseudococcidae).

When two or more parasitoid species, particularly candidates for biocontrol, share the same target in the same temporal window, a complex of behaviors can occur among them. We studied the type of interactions (competition and intraguild predation) that existed between the nymphal parasitoids Anagyrus cachamai and A. lapachosus (Hymenoptera: Encyrtidae), two candidate neoclassical biocontrol agents against the Puerto Rican cactus pest mealybug, Hypogeococcus sp. (Hemiptera: Pseudococcidae). The surrogate native congener host in Argentina, the cactus mealybug Hypogeococcus sp., was studied to predict which species should be released; in the case that both should be released, in which order, and their potential impact on host suppression. In the laboratory we conducted experiments where different densities of the host mealybug were exposed to naive females of A. cachamai and A. lapachosus sequentially in both directions. Experiments were analyzed by combining a series of competitive behavioral and functional response models. A fully Bayesian approach was used to select the best explaining models and calculate their parameters. Intraguild predation existed between A. cachamai, the species that had the greatest ability to exploit the resource, and A. lapachosus, the strongest species in the interference competition. The role that intraguild predation played in suppression of Hypogeococcus sp. indicated that a multiple release strategy for the two biocontrol agents would produce better control than a single release; as for the release order, A. lapachosus should be released first.

A new Anagyrus (Hymenoptera: Encyrtidae) from Argentina, parasitoid of Hypogeococcus sp. (Hemiptera: Pseudococcidae) on Harrisia pomanensis (Cactaceae).

A new species of Anagyrus Howard (Hymenoptera: Encyrtidae), A. lapachosus sp. n., is described from Salta Province of Argentina as a parasitoid of Hypogeococcus sp. (Hemiptera: Pseudococcidae) on Harrisia pomanensis cactus (Cactaceae). It is a candidate "new association" biological control agent for quarantine evaluation and possible following introduction to Puerto Rico (USA) against another Hypogeococcus sp., commonly called the Harrisia cactus mealybug and often misidentified as H. pungens Granara de Willink (according to our unpublished data the latter attacks only Amaranthaceae), which devastates or threatens the native cacti there and also in some other Caribbean islands (Triapitsyn, Aguirre et al. 2014; Carrera-Martínez et al. 2015).

Two new species of Anagyrus (Hymenoptera: Encyrtidae) from Argentina, parasitoids of Hypogeococcus spp. (Hemiptera: Pseudococcidae), with taxonomic notes on some congeneric taxa.

Two new species of Anagyrus Howard (Hymenoptera: Encyrtidae) are described from Argentina, A. cachamai Triapitsyn, Logarzo & Aguirre sp. n. (Catamarca, Córdoba, Salta and Tucumán Provinces) and A. quilmes Triapitsyn, Logarzo & Aguirre sp. n. (Catamarca, Salta and Tucumán). Both new species are parasitoids of Hypogeococcus spp. (Hemiptera: Pseudococcidae). Anagyrus cachamai is a parasitoid of H. pungens Granara de Willink on Alternanthera paronychioides, A. pungens and Gomphrena sp. (Amaranthaceae), and also of a Hypogeococcus sp. on Cleistocactus baumannii and Hypogeococcus sp. on C. smaragdiflorus (Cactaceae). Anagyrus quilmes is a parasitoid of H. pungens on A. paronychioides, A. pungens and Gomphrena sp. Other biological traits of the new species are also reported. These parasitoids may be of importance as potential candidate biological control agents against a Hypogeococcus sp., commonly called the Harrisia cactus mealybug and identified as H. pungens, but possibly not belonging to that species. This mealybug threatens the native cacti in some Caribbean islands and Florida, USA, and is devastating the native columnar cacti in Puerto Rico. Illustrations and taxonomic notes on the type specimens of some other, little known described species of Anagyrus from Argentina and Chile are provided, and a key to females of the 14 species of Anagyrus known from Argentina is given. Anagyrus nigriceps (De Santis) syn. n. is synonymized under A. bellator (De Santis). Lectotypes are designated for Paranusia bifasciata Brèthes, Philoponectroma pectinatum Brèthes, and Protanagyrus aciculatus Blanchard.