The genus Elasmoderus is a group of the orthopteran family Tristiridae distributed across the transitional region of South America, Andean areas of Peru, Argentina, and Chile, the low-altitude desert and semidesert territories of Chile, and the steppe areas of the Argentinian and Chilean Patagonia. This genus is endemic to the extreme arid environments of north-central Chile and is famous for its adaptations to such habitats. Based on original and published data, we characterize the geographical distribution and discuss the history and ecology of this genus. Within this genus, Elasmoderus lutescens is the most widely distributed species, mainly in coastal and interior environments, followed by E. minutus, a small-sized species with a more restricted distribution range that is currently categorized as Vulnerable in Chile. Another relevant species is Elasmoderus wagenknechti, which is concentrated in coastal and interior environments of the Coquimbo region, where it can be very abundant. This species is economically significant and can damage crops and natural vegetation. Our findings highlight the importance of researching native insects to understand the role they play in semiarid ecosystems and to develop a basis for conducting long-term studies in
northern Chile.

Plant reproductive failure is a critical concern for conserving rare and endangered species that typically have low- density and sparse populations. One important factor contributing to reproductive failure is the spatial arrangement of plants within a population, which can lead to isolation and negatively affect seed production, particularly in obligate outcrossers. Additionally, plant size can compound this effect, influencing seed production via multiple processes. Here, we investigate how spatial distribution and size influence the reproductive success of Vasconcellea chilensis, an endemic- threatened papaya species in Chile. We first examined whether V. chilensis can produce seeds via apomixis using pollinator exclusion experiments. We then used Spatial Point Pattern Analysis (SPPA) in three populations to explore the spatial arrangement of plants. Finally, we assessed whether plant size and neighbor distance influence the reproductive success V. chilensis is a dioecious shrub unable to produce fruits through apomixis. The SPPA revealed significant clustering of female and male plants at different spatial scales, indicating a non- random distribution. Moreover, a significant spatial association between the sexes was observed. In two populations, closer proximity to male plants was linked to higher seed production. Our study revealed that the reproductive system of V. chilensis is susceptible to distance- dependent reproductive failure due to pollen limitation. While the species’ spatial structure may partially mitigate this risk, female plants isolated from male counterparts will likely experience reduced seed set.