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In many insects, short photoperiods induce females to lay diapausing eggs, which are associated with a reduction in female fecundity, and/or with an increase in their growth rate, allowing for a larger size at adulthood. The effects of short photoperiods may also differ among populations, depending on the different selection pressures imposed by the winter conditions. Thus, this study aimed to experimentally assess the effects of short photoperiods on Aedes aegypti , an invasive mosquito species that also vectors several viral diseases. We compared life history parameters of the females reared from the first larval instar under contrasting photoperiods, in two populations from the temperate region of Argentina, one with a milder winter (BA) and the other with a harsher winter (SB). The results showed a significant increase in the time to oviposition, a trend to a larger size of females (significant only for SB) and higher inhibition of egg hatching (more pronounced in SB), in response to short photoperiods. No differences in fecundity were detected among treatments. The different reaction norms of the populations in female body size and egg hatching response suggest an adaptation to local conditions, which might favour a further expansion of A. aegypti towards colder climates. [ABSTRACT FROM AUTHOR]

This article offers an analysis of the encounter between the two natural environments of the Italian Po Plain and the Argentinian Pampa Gringa through the migration of Italian rural workers. Notably, we focus on the migration micro-histories of Emiliano-Romagnoli, who moved from Italy to Argentina during Italian Great Migration Era (1870–1955). Building on oral histories gathered in Italy and Argentina between 2005 and 2007, these micro-histories show how place-based landscapes of Italianness hybridised with the local landscape of the South American plains through Italian migrants' embodied memories, labour, and socio-environmental transformation practices. By focusing on Po Plain migrants' memories and experiences of the lowlands of northern Italy and the Argentinian pampas, we aim to offer a micro-historical perspective on the environmental history of migration. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this paper is to explore and elaborate on how institutional conditions work to the advantage and disadvantage of disaster risk reduction (DRR) policies on different levels in two countries.Design/methodology/approach A qualitative case study design is used to study empirically two countries with very different traditions when it comes to political-administrative institutions: Argentina and Sweden.Findings As expected, the institutional foundations of DRR policy in Sweden are shown to be more consistent and stable than in Argentina. However, this difference is of less importance when considering the crucial role of local practices. National institutional foundations can function as support – but is not a necessary condition – for building disaster preparedness on the ground. The authors argue that national governments cannot do without institutionalized praxis-based preparedness, which is vital for both effective emergency management and learning.Originality/value This paper contributes to the disaster research debate by elaborating on institutional arrangements that can facilitate or hinder DRR strategies in a multi-level context. The main argument is that institutional practices on the ground are important to compensate for insufficient national institutions, either because they are weak or too distant from practical DRR. The authors also elaborate on how institutional practices can function as a source for learning and for building legitimate practical authority from the bottom up. [ABSTRACT FROM AUTHOR]

Buenos Aires city is located near the southern limit of the distribution of Aedes aegypti (Diptera: Culicidae). This study aimed to assess long-term variations in the abundance of Ae. aegypti in Buenos Aires in relation to changes in climatic conditions. Ae. aegypti weekly oviposition activity was analyzed and compared through nine warm seasons from 1998 to 2014, with 200 ovitraps placed across the whole extension of the city. The temporal and spatial dynamics of abundances were compared among seasons, and their relation with climatic variables were analyzed. Results showed a trend to higher peak abundances, a higher number of infested sites, and longer duration of the oviposition season through subsequent years, consistent with a long-term colonization process. In contrast, thermal favorability and rainfall pattern did not show a consistent trend of changes. The long-term increase in abundance, and the recently documented expansion of Ae. aegypti to colder areas of Buenos Aires province suggest that local populations might be adapting to lower temperature conditions. The steadily increasing abundances may have implications on the risk of dengue transmission. [ABSTRACT FROM AUTHOR]

• Short parental photoperiod inhibited the hatching response of Aedes aegypti eggs. • The hatching response increased with eggs age up to four months. • No effect of the storage photoperiod on the hatching response was detected. • The hatching response was highly variable among egg batches from different females. Dormancy is a developmental arrest in arthropods, in response to unfavorable conditions in temporally varying environments. In Aedes aegypti , the supposed inability of eggs to inhibit hatching has been used to explain the restriction of this species to tropical and subtropical regions. However, the geographic range of Ae. aegypti is constantly expanding towards temperate regions. Thus, the aim of the present study was to assess the ability of Ae. aegypti individuals from a temperate region (Buenos Aires City, Argentina) to enter photoperiod induced dormancy. To this end, we exposed both the parental generation and the eggs to short-day (SD: 10L:14D) and long-day (LD: 14L:10D) photoperiods, and studied the temporal variation in egg hatching. The experiment consisted of 28 treatment combinations of three factors: parental photoperiod (SD or LD), egg storage photoperiod (SD or LD), and age of eggs (14, 28, 42, 56, 70, 91, and 112 days). The results showed a lower hatching response with the SD parental photoperiod, and a trend to higher hatching with longer egg storage time in all photoperiod treatment combinations. The egg storage photoperiod showed no effect on egg hatching. In both parental photoperiod treatments, egg replicates of most ages from different females showed a large variability, with some replicates with lowest hatching response and others with highest hatching response. Our results show the ability of Ae. aegypti to inhibit egg hatching in response to a short-day photoperiod, which could allow the further expansion of this species to regions with colder winters. [ABSTRACT FROM AUTHOR]