Consistent Pattern of Local Adaptation during an Experimental Heat Wave in a Pipefish-Trematode Host-Parasite System

Extreme climate events such as heat waves are expected to increase in frequency under global change. As one indirect effect, they can alter magnitude and direction of species interactions, for example those between hosts and parasites. We simulated a summer heat wave to investigate how a changing environment affects the interaction between the broad-nosed pipefish (Syngnathus typhle) as a host and its digenean trematode parasite (Cryptocotyle lingua). In a fully reciprocal laboratory infection experiment, pipefish from three different coastal locations were exposed to sympatric and allopatric trematode cercariae. In order to examine whether an extreme climatic event disrupts patterns of locally adapted host-parasite combinations we measured the parasite's transmission success as well as the host's adaptive and innate immune defence under control and heat wave conditions. Independent of temperature, sympatric cercariae were always more successful than allopatric ones, indicating that parasites are locally adapted to their hosts. Hosts suffered from heat stress as suggested by fewer cells of the adaptive immune system (lymphocytes) compared to the same groups that were kept at 18°C. However, the proportion of the innate immune cells (monocytes) was higher in the 18°C water. Contrary to our expectations, no interaction between host immune defence, parasite infectivity and temperature stress were found, nor did the pattern of local adaptation change due to increased water temperature. Thus, in this host-parasite interaction, the sympatric parasite keeps ahead of the coevolutionary dynamics across sites, even under increasing temperatures as expected under marine global warming

Resistência ao Estresse Calórico em Frangos de Corte de Pescoço Pelado Resistance to Heat Stress of Naked Neck Broilers

Aves de duas linhagens, sendo uma portadora do gene pescoço pelado (Na_) que determina redução no empenamento, e outra não portadora, com empenamento normal (nana), foram submetidas a estresse térmico gradativo (38, 40 e 42ºC), em câmara climática, nas idades de 28, 35 e 42 dias, com o intuito de se verificar a resistência ao estresse térmico. Foram verificadas diferenças significativas entre a temperatura retal média e a taxa respiratória média da linhagem de empenamento normal quando comparada com a linhagem de pescoço pelado, em todas as idades e períodos de estresse. Foram verificados valores mais altos das aves de empenamento normal, demonstrando a influência do conjunto temperatura de estresse térmico e idade. Pôde-se constatar que houve diferença significativa entre as linhagens para as médias de perda de peso apenas aos 35 dias de idade. Os resultados obtidos sugerem que a linhagem de pescoço pelado (Na_) possui maior resistência ao estresse térmico em relação à linhagem de empenamento normal (nana).<br>Birds of two lineages, a carrier of the Naked Neck gene (Na_) that determines reduction in the feathering and other non-carrier (normal feathering, nana), were submitted to thermal stress (38, 40 and 42ºC) in climatic chambers at 28, 35 and 42 days of age to verify the resistance to the thermal stress. Significant differences were verified among the mean rectal temperature of the normal feathered lineage when compared with the naked neck lineage, in all the ages and stress periods, with higher values in the normal feathered birds. The same result was found for mean respiratory rate. Significant difference was found for weight loss between the two lineages only at the age of 35 days. The results obtained suggest that the Naked Neck lineage possesses higher resistance to the thermal stress in relation to the normal feathered lineage

Is being conservative at home whilst taking risks abroad a suitable competitive strategy? The case of Spanish Family Firms internationalizing to Mexico

Family firms’ (FFs) importance for industrialized and developing countries and the growing competition has led to an increased interest in knowing how FFs develop their competitive strategies. Since FFs usually have a long-term vision when deciding how to compete, analyzing competitive strategies –usually linked with the long-term– makes even more sense. Furthermore, FFs’ behavior is especially interesting when they have been internationalized. Thus, the purpose of our study is to improve the understanding of the competitive strategies of FFs’ internationalizing to Mexico, namely exploitation (at a national level) and exploration (at international level). Briefly, a firm’s exploitation strategy is characterized by better-using firms’ existing resources and knowledge, whereas a firm’s exploration strategy involves exploring new ways of doing. Based on data collected from 81 CEOs of Spanish firms that have been internationalized to Mexico, we use partial least squares structural equation modeling (PLS-SEM) technique. We conclude that FFs’ exploitation strategy (at a national level) has a positive impact on firms’ exploration strategy (at international level). In other words, being more efficient and leveraging current knowledge at a national level helps to pursue opportunities internationally actively