Two new species of Chaetocnema Stephens from South Africa (Coleoptera: Chrysomelidae, Galerucinae, Alticini)

Biondi, Maurizio; D’Alessandro, Paola

doi:10.4081/fe.2018.279

Cited by 3 publications

(1 citation statement)

References 14 publications

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“…It consists of over 300 described species. About the Afrotropical region, Chaetocnema genus includes over 100 known species ( Biondi, 2002 ; Biondi & D’Alessandro, 2006a , 2006b , 2018 ). The species of this genus are often associated with moist environments and plants in many botanical families, particularly the Chenopodiaceae, Polygonaceae, Cyperaceae, Gramineae ( Biondi, Urbani & D’Alessandro, 2015 ).…”

Section: Methodsmentioning

confidence: 99%

Climate change favours connectivity between virus-bearing pest and rice cultivations in sub-Saharan Africa, depressing local economies

Iannella¹,

Simone²,

D’Alessandro³

et al. 2021

PeerJ

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Aims Rice is a staple food for many countries, being fundamental for a large part of the worlds’ population. In sub-Saharan Africa, its importance is currently high and is likely to become even more relevant, considering that the number of people and the per-capita consumption are both predicted to increase. The flea beetles belonging to the Chaetocnema pulla species group (pulla group), a harmful rice pest, are an important vector of the Rice Yellow Mottle Virus, a disease which leads even to 80–100% yield losses in rice production. We present a continental-scale study aiming at: (1) locating current and future suitable territories for both pulla group and rice; (2) identifying areas where rice cultivations may occur without suffering the presence of pulla group using an Ecological Niche Modelling (ENM) approach; (3) estimating current and future connectivity among pulla group populations and areas predicted to host rice cultivations, based on the most recent land-use estimates for future agricultural trends; (4) proposing a new connectivity index called “Pest Aggression Index” (PAI) to measure the agricultural susceptibility to the potential future invasions of pests and disease; (5) quantifying losses in terms of production when rice cultivations co‐occur with the pulla group and identifying the SSA countries which, in the future inferred scenarios, will potentially suffer the greatest losses. Location Sub-Saharan Africa. Methods Since the ongoing climate and land-use changes affect species’ distributions, we first assess the impact of these changes through a spatially-jackknifed Maxent-based Ecological Niche Modelling in GIS environment, for both the pulla group and rice, in two climatic/socioeconomic future scenarios (SSP_2.45 and 3.70). We then assess the connectivity potential of the pulla group populations towards rice cultivations, for both current and future predictions, through a circuit theory-based approach (Circuitscape implemented in Julia language). We finally measure the rice production and GPD loss per country through the spatial index named “Pest Aggression Index”, based on the inferred connectivity magnitude. Results The most considerable losses in rice production are observed for Liberia, Sierra Leone and Madagascar in all future scenarios (2030, 2050, 2070). The future economic cost, calculated as USD lost from rice losses/country’s GDP results are high for Central African Republic (−0.6% in SSP_2.45 and −3.0% in SSP_3.70) and Guinea–Bissau (−0.4% in SSP_2.45 and −0.68% in SSP_3.70), with relevant losses also obtained for other countries. Main conclusions Since our results are spatially explicit and focused on each country, we encourage careful land-use planning. Our findings could support best practices to avoid the future settlement of new cultivations in territories where rice would be attacked by pulla group and the virus, bringing economic and biodiversity losses.

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Section: Methodsmentioning

confidence: 99%

Climate change favours connectivity between virus-bearing pest and rice cultivations in sub-Saharan Africa, depressing local economies

Iannella¹,

Simone²,

D’Alessandro³

et al. 2021

PeerJ

Self Cite

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Fine-Tuned Ecological Niche Models Unveil Climatic Suitability and Association with Vegetation Groups for Selected Chaetocnema Species in South Africa (Coleoptera: Chrysomelidae)

2022

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Despite beetles (Coleoptera) representing most existing animal species, the ecological and biogeographical factors shaping their distribution are still unclear in many regions. We implemented state-of-the-art Ecological Niche Models (ENMs) and niche overlap analysis to investigate climate-occurrence patterns for five flea beetle species of the genus Chaetocnema in South Africa (C. brincki, C. danielssoni, C. darwini, C. gahani and C. natalensis). ENMs were fitted through Maxent and Random Forests, testing various parameterizations. For each species, tuned ENMs attaining good discrimination on spatially independent test data were selected to predict suitability across the study region and individuate its main climatic drivers. Percent coverage of climatically suitable areas by seventeen Afrotropical vegetation formations was also computed. Predicted suitable areas do not extend far away from known presence localities, except for C. brincki and C. gahani in north-eastern South Africa. Temperate grasslands and shrublands cover most of suitable areas for C. brincki and C. gahani, along with warm temperate forests, as well as for C. danielssoni, in this case being followed by tropical flooded and swamp forests. Climatic suitability for C. darwini mainly relates to the Mediterranean grasslands and scrublands of the southern coastal region, while suitable areas for C. natalensis encompass various vegetation formations, coherently with its wide distribution. The environmental niche of C. danielssoni significantly overlaps with those of the wide-ranging C. darwini and C. natalensis, suggesting that historical factors, rather than low climatic tolerance, has determined its restricted distribution in the Western Cape Province. Maxent and Random Forests were confirmed to be of great help in disentangling the environment – occurrence relationships and predict suitability for the target species outside their known range, but they need to be properly tuned to perform at their best.

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Taxonomic revision of the Calotheca parvula species group from southern Africa, with descriptions of three new species (Coleoptera, Chrysomelidae)

D’Alessandro¹,

Iannella²,

Grobbelaar³

et al. 2021

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Calotheca Heyden, 1887 is a flea beetle genus that occurs predominantly in sub-Saharan Africa, comprising 29 species. The examination of new material is revealing a significantly higher species richness and high intraspecific variability. A group of five species, occurring in the southernmost portion of the distribution range for the genus, is here attributed to the C. parvula species group: C. parvula (Weise, 1908), C. pallida (Bryant, 1945), C. danielssonisp. nov., C. oberprielerisp. nov., and C. prinslooisp. nov. Species in the C. parvula group have strong similarities in body shape and sculpture on the integument, spermathecal shape, and for most species the morphology of the median lobe of the aedeagus. A key to species of the Calotheca parvula group is provided along with photographs of the habitus, main diagnostic characters, median lobe of the aedeagus and spermatheca. In addition to the geographic distribution, the available information on the habitat, host plants, and phenology are provided for the five species analysed.

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Two new species of Chaetocnema Stephens from South Africa (Coleoptera: Chrysomelidae, Galerucinae, Alticini)

Cited by 3 publications

References 14 publications

Climate change favours connectivity between virus-bearing pest and rice cultivations in sub-Saharan Africa, depressing local economies

Climate change favours connectivity between virus-bearing pest and rice cultivations in sub-Saharan Africa, depressing local economies

Fine-Tuned Ecological Niche Models Unveil Climatic Suitability and Association with Vegetation Groups for Selected Chaetocnema Species in South Africa (Coleoptera: Chrysomelidae)

Taxonomic revision of the Calotheca parvula species group from southern Africa, with descriptions of three new species (Coleoptera, Chrysomelidae)

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