Nematodes (Mermithidae) parasitizing grasshoppers (Orthoptera: Acrididae) in the Pampean region, Argentina

Abstract

This work provides the results of a survey of entomonematodes parasites of grasshoppers in grasslands of the Pampean Region, Argentina. Camino and Stock, 1989. The values of parasitism ranged between 1-12%, and intensity not overcome the number of 5.0 nematodes per larva. The nematodes observed showed specificity, not registering the same species of parasite in more than one host species. The Pampean region constituted an area with high diversity of mermithids where new species could be consider as bioregulator agents of this troublesome insect pests in agricultural areas of Argentina.Keywords: nematodes, Acrididae, pest, agriculture, Argentina. Nematóides (Mermithidae) parasitando gafanhotos (Orthoptera: Acrididae) nos Pampas região, a Argentina ResumoEste trabalho apresenta os resultados de uma pesquisa entomonematode parasitando gafanhotos em pastagens da região pampeana, Argentina. Ninfas de Staurorhectus longicornis Giglio-Tos, Laplatacris dispar Rhen de 1939, Dichroplus elongatus Giglio-Tos, 1894 e Metaleptea brevicornis (L.) (Orthoptera: Acrididae) foram coletados. Mermithidae era a única família registrado com sete espécies: Agamermis decaudata Cobb, Steiner and Christie, 1923, Amphimermis bonaerensis Miralles and Camino, 1983, Amphimermis dichroplusi Camino and Lange, 1997, Amphimermis ronderosi Camino and Lange, 1997, Hexamermis coclhearius Stock and Camino, 1992, Hexamermis ovistriata Stock and Camino, 1992, e Longimermis acridophila Camino and imagem, de 1989. Os valores de parasitismo variou entre 1-12%, e intensidade não superar o número de 5,0 nematóides por larva. Os nemátodos observados demonstraram especificidade, não registar as mesmas espécies de parasita em mais do que uma espécie de hospedeiro. A região pampeana constituída uma área com alta diversidade de mermithids onde novas espécies poderiam ser consideradas como agentes bio-reguladores deste incômodos insetos pragas em áreas agrícolas da Argentina.

Symbiosis of the millipede parasitic nematodes Rhigonematoidea and Thelastomatoidea with evolutionary different origins

“…Interestingly, R. naylae infected all of the millipedes. Cephalobellu s is a member of the family Thelastomatidae and is found in many invertebrate hosts, including mole crickets, crane flies, white grubs, cockroaches, and millipedes [ 14 , 29 , 60 ]. In addition, we isolated nematode genera from the mole cricket Gryllotalpa orientalis , white grub Protaetia orientalis submarumorea , and pill millipedes Hyleoglomeris japonica (data not shown).…”

First record of a mermithid worm (Nematoda, Mermithidae) parasitizing a third instar nymph of Triatoma sordida (Stål, 1859) (Hemiptera, Reduviidae, Triatominae) from Mato Grosso, Brazil

“…2016). The majority of mermithid species constitute a significant regulatory influence on the population dynamics of plague insects (Rusconi et al 2017).…”

“…These eggs are later consumed by the insects along with the vegetal material and hatch in the gut; the juveniles subsequently pass through the gut wall into the hemocoel and considerably increase in size inside the host. Nematodes kill the host with their emergence to the soil where they molt into the adult stage to complete the cycle (Poinar-Jr. 1979;Rusconi et al 2017).…”

“…Nematodes kill the host with their emergence to the soil where they molt into the adult stage to complete the cycle (Poinar-Jr. 1979). Emergence from its host by killing it, places them as parasitoids (Rusconi et al 2017).…”

“…Information about Mermithidae nematodes is scarce. In South America, there are a few studies about terrestrial mermithids in grasshoppers (Miralles and Camino 1983;Camino and Stock 1989;Camino and Lange 1997;Rusconi et al 2017) and ants (Jouvenaz and Wojcik 1990;Poinar-Jr. et al 2007) from Argentina. In Brazil, Rodrigues et al (2005) reported an unidentified Mermithidae larva emerging from spiders from Brazil and Peru.…”