Relationship between pest grasshopper densities and climate variables in the southern Pampas of Argentina

Abstract

Grasshoppers are one of the most predominant insects in the grasslands of the southern Pampas. In this region, Dichroplus elongatus, Dichroplus maculipennis, Dichroplus pratensis and Borellia bruneri are the most abundant species and have the greatest economic importance. This study aimed to assess the relationship between temporal changes in the density of these species and climate variables associated with temperature and rainfall over an 11-year study period., We monitored 22 sites in different areas of Laprida county from 2005 to 2016. A total of 25 grasshopper species were collected. The most abundant species were D. maculipennis and B. bruneri which reached the highest densities from 2008–2009 to 2010–2011. The rainfall accumulated from September (RAS) to the sampling date and the number of rainy days (RD) largely explained the density variation of B. bruneri. Besides RD and RAS, winter rainfall, rainfall accumulated from October to the sampling date, and thermal amplitude of October (TAO) influenced the density of D. maculipennis. Our results indicated that seasons with less rainfall and fewer RD favored these two species’ abundance. We identified that the RD and TAO contributed significantly to variations in the density of D. elongatus. In contrast to the other two species, we recorded D. elongatus in seasons with high rainfall and high RD. A better understanding of the climate influence on the life cycle of these economically important insects may identify key factors in their population dynamics which in turn may improve management options.

Grasshopper (Orthoptera: Acridoidea) diversity in the Pampas region of Argentina: status as revealed by long-term sampling

“…Along with D. maculipennis, the gomphocerine B. bruneri, which is recognized as a pest in the Pampas region of Uruguay (Lorier et Regarding the estimated beta diversity, the temporal composition patterns at the SW, W, and NW sites was mostly de ned by species turnover over the years. This variability in species composition could be linked to changes in land use as well as environmental variables that favor the life cycle of some species more than others (Mariottini et al 2022). Distinctly, in the SE nestedness was the main component.…”

“…Furthermore, the NW zone exhibited the lowest completeness pro le in terms of species richness, suggesting that approximately 31% of the rare species went undetected in the samples. In spite of relatively recent contributions on the structure and dynamics of grasshoppers in the Pampas (Torrusio et al 2002;De Wysiecki et al 2004;Mariottini et al 2011;2022), our understanding of ecological aspects concerning rare species remains limited because such contributions were mostly focused on agriculturally harmful species, usually those that are the most abundant, frequent or common. In this sense, results of the indexes we employed (ACE) showed that the grasshopper communities in each of the zones were structured with relatively few dominant species in terms of abundance and many rare species.…”

Polistes dominula (Hymenoptera: Vespidae) paper wasps detect native grasshoppers using olfactory cues

“…Polistes dominula (Hymenoptera: Vespidae) paper wasps detect native grasshoppers using olfactory cues In the Patagonian steppe, there is a wide diversity and abundance of phytophagous insects, among which native grasshoppers represent one of the main groups inhabiting pastures, including steppe wetlands and pampas (Carbonell et al, 2006;Lange et al, 2005;Mariottini et al, 2011;Roig-Juñent et al, 2014). At present, many species of grasshoppers are considered pests because they can cause severe economic losses due to their voracity, consuming both natural and implanted pastures (Carbonell et al, 2006;Mariottini et al, 2011).…”

“…Polistes dominula (Hymenoptera: Vespidae) paper wasps detect native grasshoppers using olfactory cues In the Patagonian steppe, there is a wide diversity and abundance of phytophagous insects, among which native grasshoppers represent one of the main groups inhabiting pastures, including steppe wetlands and pampas (Carbonell et al, 2006;Lange et al, 2005;Mariottini et al, 2011;Roig-Juñent et al, 2014). At present, many species of grasshoppers are considered pests because they can cause severe economic losses due to their voracity, consuming both natural and implanted pastures (Carbonell et al, 2006;Mariottini et al, 2011). Particularly, Dichroplus elongatus (Giglio-Tos) (Orthoptera: Acrididae, Melanoplinae) is one of the most abundant grasshopper species in this region, which feeds on forbs and grasses and therefore constitutes a potential pest in grasslands and crops in Argentina (Carbonell et al, 2006;Cigliano & Lange, 1998;Cigliano & Otte, 2003).…”

Efectos de la fragmentación y modificación del Pastizal Serrano del Sistema de Tandilia sobre las poblaciones de aves de pastizal

“…Estas nidadas tempranas desde fines de septiembre estuvieron lideradas por el Pecho Amarillo Chico, y esto coincide con lo reportado para esta especie en pastizales de la pampa deprimida (Mermoz y Reboreda 1998). Los pastizales pampeanos albergan una amplia diversidad de artrópodos que incluye especies depredadoras, polinizadoras y herbívoras (Sabatino et al 2010;Mariottini et al 2011;Schwerdt et al 2014). Tanto para los artrópodos depredadores y polinizadores, se observa una mayor abundancia de los mismos entre los meses de septiembre y diciembre, con un pico en el mes de noviembre (Schwerdt et al 2014;Sabatino Malena et al 2021).…”