Multivariate discrimination among cryptic mites of the genus Androlaelaps (Acari: Mesostigmata: Laelapidae) parasitic of sympatric akodontine rodents (Cricetidae: Sigmodontinae) in northeastern Argentina: possible evidence of host switch followed by speciation, with the description of two new species

Abstract

Laelapids are among the most common ectoparasites of rodents. Currently, it is under discussion whether there is a single polixenous species that parasites a variety of hosts, or whether there are cryptic species highly host specific. Herein, multivariate morphometric analyses of cryptic sympatric laelapids of the genus Androlaelaps allowed us to identify different species. These species are specific of their akodontine hosts, Akodon montensis and Thaptomys nigrita, in localities situated in northeastern Argentina. In addition, we analyzed similar laelapids associated with the akodontines Deltamys kempi and Akodon cursor. Using principle component analyses we differentiated four laelapid species, each one host specific, independent of sympatry of the hosts, and without geographical variation. From these four species, we described two new species (Androlaelaps navonae n. sp. and Androlaelaps wingei n. sp.). We determined the four species based on a range of variations in several characters, mainly size. These four laelapid species belong to the Androlaelaps rotundus species group, specific to akodontines. These species are very similar among them but differ from the remainder species of the group by their small size, distance between j6 setae similar to the distance between the z5 setae, strong ventral setae, opisthogaster with 13 pairs of strong setae (one close to the distal margin of epigynal shield), and anal shield wider than long. Further studies will elucidate whether they constitute a new laelapid genus. Phylogenetic and ecological factors influencing host-specificity are discussed, and we propose that host colonization could have taken place by host switching of a single laelapid species among rodent species, followed by speciation.

Ectoparasites associated with sigmodontine rodents from northeastern Argentina

“…Every mite-host associated reported herein was previously reported for other areas. Androlaelaps ulysespardinasi and A. rotundus, belong to the Androlaelaps rotundus species group, which includes host specific species associated with different akodontine rodents (Lareschi and Galliari 2014;. Laelaps manguinhosi, L. paulistanensis, Mysolaelaps spp., and Gigantolaelaps spp.…”

Cryptic speciation in the Acari: a function of species lifestyles or our ability to separate species?

“…Many experts suspect the existence of significantly more cryptic diversity in Acari than is currently known (e.g. Walter and Campbell 2003 ; Knee et al 2012 ; Stålstedt et al 2013 ; Engelbrecht et al 2014 ; Lareschi and Galliari 2014 ). On the basis of literature mining we show a demonstrable need for future investigations that will unveil potentially hidden mite species and identify evolutionary mechanisms behind cryptic speciation within Acari.…”

Morphometric variation of Androlaelaps fahrenholzi (Mesostigmata: Laelapidae) associated with three Sigmodontinae (Rodentia: Cricetidae) from the north of Chile

“…The same authors further analyzed Laelaps differens (Fonseca) showing the presence of two groups, one associated to the host C. scotti from Distrito Federal and the other associated with C. goytaca from Restinga de Jurubatiba (Brazil). More recently, Lareschi and Gallieri (2014) studied A. rotundus through PCA identifying four groups of mites, each host specific and without geographical variation. Each group corresponded to a new species that differed by group means of particular measurements.…”

“…Each group corresponded to a new species that differed by group means of particular measurements. Lareschi and Gallieri (2014) propose that these different morphs exist because mites change hosts, followed by a process of speciation, based mainly in the fact that Laelapideae inhabit the nests of their hosts and may colonize new hosts by nest sharing and/or by overlap of geographic host ranges. The same thing could be happening in A. fahrenholzi, a species associated with nests of its hosts (Strandtmann and Wharton 1958;Radovsky 1994;Krantz and Walter 2009).…”