Systematic revision of the Savignia genus group (Araneae: Linyphiidae: Erigoninae) with notes on their cephalic lobe evolution

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  Systematic revision of the Savignia genus group (Araneae: Linyphiidae: Erigoninae) with notes on their cephalic lobe evolution Abstract The Savignia genus group includes nine morphologically complex yet similar genera where species were assigned based mainly on the cephalic lobes. Among these genera, males of Diplocephalus Bertkau, 1883, Savignia Blackwall, 1833 and Araeoncus Simon, 1884 show some of the most extraordinary cephalic lobes among dwarf spiders (Linyphiidae, Erigoninae). In this study we undertake the first phylogenetic analysis of the Savignia genus group. We use 269 morphological characters (175 newly defined) and 70 taxa (59 ingroup taxa) to reconstruct the relationships and evolutionary trends of cephalic lobes in this lineage. Our findings show that cephalic lobes with varying shapes and sizes appear in several Savignia genus group lineages, highlighting that it is not a good diagnostic character. The high support in several clades allows the redefinition of t...

Seasonal variation of arthropod diversity in agroforestry systems in the humid tropics of Mexico

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Seasonal variation of arthropod diversity in agroforestry systems in the humid tropics of Mexico

Abstract

Agroforestry systems in the tropics exhibit high heterogeneity in plant species composition and structural configuration. However, few studies evaluated the seasonal shift in arthropod alpha diversity and abundance in agroforestry systems in the tropics. This study was designed to analyze the composition, abundance, and alpha diversity of arthropod orders in five agroforestry systems in the humid tropic of Tabasco, Mexico. The agroforestry systems compared were shade trees in plantations (ShTP), living fences (LF), alley farming (AF), slash-and-burn agriculture (SBA), and grazing plantations (GP) during dry and rainy seasons. Arthropods were collected using pitfall traps, classified at the order level, and counted to estimate the abundance. A total of 10,271 arthropod individuals were collected that belong to seven orders. Hymenoptera was the most abundant group, accounting for 64.7% of the total count, followed by Coleoptera, Collembola, Araneae, Hemiptera, Diptera, and Orthoptera. Arthropod alpha diversity and abundance varied significantly among the agroforestry systems and between the rainy and dry seasons. The agroforestry systems AF, GP, and ShTP showed a higher diversity (Shannon index) and dominant orders (Simpson index) in the rainy season compared to the dry season. The seasonal shift of the different arthropod orders varied among agroforestry systems, while the Orthoptera did seasonally vary across the agroforestry systems. This study suggests the interactive effects of seasons and agroforestry systems on arthropod abundance and diversity.

Lara-Pérez, L.A., Villanueva-López, G., Oros-Ortega, I. et al. Seasonal variation of arthropod diversity in agroforestry systems in the humid tropics of Mexico. Arthropod-Plant Interactions (2023). https://doi.org/10.1007/s11829-023-10001-0