Ecological implications on the aggregation of Amblyomma fuscum (Acari: Ixodidae) on Thrichomys laurentius (Rodentia: Echimyidae), in northeastern Brazil

Abstract

We investigated the Amblyomma fuscum load on a pullulating wild rodent population and the environmental and biological factors influencing the tick load on the hosts. One hundred and three individuals of Thrichomys laurentius were caught in an Atlantic forest fragment in northeastern Brazil, as part of a longitudinal survey on ticks infesting non-volant small mammals. Ticks (n = 342) were found on 45 individuals and the overall mean intensity of infestation was 7.6 ticks per infested rodent. Ticks were highly aggregated in the host population and the negative binomial distribution model provides a statistically satisfactory fit. The aggregated distribution was influenced by sex and age of the host. The microhabitat preference by T. laurentius probably increases contact opportunities between hosts and aggregated infesting stages of the ticks and represents important clues about the habitat suitability for A. fuscum.

Amblyomma mixtum free-living stages: Summer and winter use, preference, and niche width in an agroecosystem (Yopal, Casanare, Colombia)

“…According to [31,87], leaf litter is often a shelter for ticks in extreme weather conditions, particularly because its structure retains moisture and provides a stable temperature for ticks. In addition, potential ground hosts for tick sub-adults [88,89] may find food or protection in the leaf litter.…”

“…That is, A. mixtum ’s preference for various habitats in a single agroecosystem, the role that the domestic and wild host community would play there, the competition for resources from those habitats with other ticks, and the associated dynamics of rickettsial infection in local animals and humans are not known. Some examples of research on ixodids of vector-pathogen-host relationships are Ixodes scapularis [30]; Amblyomma fuscum [31]; Amblyomma americanum [32]; Amblyomma aureolatum and Amblyomma ovale [33]; Amblyomma triste [34]; Ixodes ricinus [35]; Ixodes pacificus [36]; Amblyomma tuberculatum [37]; Rhipicephalus microplus [38], and Amblyomma maculatum [39].…”

“…That is, A. mixtum's preference for various habitats in a single agroecosystem, the role that the domestic and wild host community would play there, the competition for resources from those habitats with other ticks, and the associated dynamics of rickettsial infection in local animals and humans are not known. Some examples of research on ixodids of vector-pathogen-host relationships are Ixodes scapularis [30]; Amblyomma fuscum [31];…”

“…The connectivity between the studied habitats by the constant transit of diverse hosts could help to colonize temporarily new or hostile, transformed or marginal habitats, as well as to serve as a rescue mechanism for tick populations in unsuitable habitats, where the mortality rate exceeds the birth rate [106][107][108]. Thus, some hosts serve as a bridge between habitats, either because in such habitats those hosts find food [32,109] or refuge from potential predators [31]. In turn, ticks take advantage of this dispersal mechanism even when the primary hosts are absent [36] or have been anthropogenically restricted [110], seeing a possibility of expansion, as they are opportunistic on modified fragmented and crop-based systems [111].…”

Amblyomma mixtum free-living stages: Inferences on dry and wet seasons use, preference, and niche width in an agroecosystem (Yopal, Casanare, Colombia)

“…Ticks of the Amblyomma genus have been recognized as vectors of rickettsial agents to humans and animals in a number of countries; thus, the importance of their study [ 15 ]. Some examples of research on ixodids of vector-pathogen-host relationships are Ixodes scapularis [ 16 ]; Amblyomma fuscum [ 17 ]; Amblyomma americanum [ 18 ]; A . aureolatum and Amblyomma ovale [ 19 ]; Amblyomma triste [ 20 ]; Ixodes ricinus [ 21 ]; Ixodes pacificus [ 22 ]; Amblyomma tuberculatum [ 23 ]; Rhipicephalus microplus [ 24 ], Amblyomma maculatum [ 25 ], and Amblyomma sculptum [ 26 – 28 ] and Amblyomma tonelliae [ 29 ], both from the Amblyomma cajennense species complex [ 30 ].…”