Rare case of Microsporidia co-infection in the grasshopper Dichroplus elongatus (Orthoptera: Acrididae: Melanoplinae)

Abstract

Two Microsporidia species are known to parasitize Dichroplus elongatus in the Pampas region of Argentina, allochthonous Paranosema locustae, a generalist pathogen of the adipose tissue of grasshoppers with efficient horizontal and vertical transmission routes, and autochthonous Liebermannia dichropluse, a D. elongatus-specific pathogen of the Malpighian tubules with effective transovarial transmission but unknown horizontal transfer. Long-term monitoring of grasshopper communities for detection of microsporidioses revealed that it is not often that these two pathogens co-exist in populations of D. elongatus, even in different individuals. We report the unusual detection for the first time of a co-infection by P. locustae and L. dichroplusae in D. elongatus at a site in the southern Pampas. Given the own traits that characterize both pathogens we presume that the most likely scenario for the occurrence of the observed mixed infection is that the affected D. elongatus individual was already infected by L. dichroplusae when it contracted infection by P. locustae. Unfortunately, our attempts to induce infections with L. dichroplusae in the laboratory through experimental inoculations have not produced positive results, preventing efforts towards testing our presumption through laboratory bioassays. However, Microsporidia natural mixed infections appear to be so rare that we believe this case is worth reporting.

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

“…(2011), we could infer that the abundance of the mixed-feeder D. elongatus would respond favorably to the increase in forage quality and quantity associated with spring and summer rainfall. This melanopline is a ubiquitous species that may readily become a serious pest (Lange and Cigliano, 2019 b ). It seems to show the ability to adapt to different environments, and it is abundant in grasslands subjected to grazing by cattle with high coverage of forbs.…”

Diversity, Distribution, and Development of Hyperparasitic Microsporidia in Gregarines within One Super-Host

“…These parasites, in the case of mixed infection, are expected to be under resource competition, as their host represents a limited resource [ 35 ]. Mixed infections appear to be widespread among microsporidia [ 35 , 36 , 37 , 38 , 39 , 40 ]. In the case of co-infection of a multicellular host, interactions between microsporidia may be antagonistic: one species can moderate the effect of another one, and even exclude it from some organs, or it can negatively affect transmission of the concurrent species, or influence indirectly through the effects on the host life cycle [ 35 , 41 ].…”

Diversity, Distribution and Development of Hyperparasitic Microsporidia in Gregarines within One Super-host

“…These parasites, in the case of mixed infection, are expected to be under resource competition, as their host represents a limited resource [35]. In the case of co-infection with microsporidia, the host (grasshopper Dichroplus elongatus) is getting parasitized by a generalist microsporidian species (like Paranosema locustae) and a specialist one (like Liebermannia dichroplusae) [36]. Mixed infections appear to be widespread among microsporidia [35][36][37][38][39][40].…”

“…In the case of co-infection with microsporidia, the host (grasshopper Dichroplus elongatus) is getting parasitized by a generalist microsporidian species (like Paranosema locustae) and a specialist one (like Liebermannia dichroplusae) [36]. Mixed infections appear to be widespread among microsporidia [35][36][37][38][39][40]. Some interactions between co-existing microsporidia may be antagonistic, as one species under certain conditions can moderate the effect of infection by other microsporidia and even exclude them from some organs [35].…”