Intraguild interactions between five congeneric species ofThaparocleidus(Monogenoidea) from the freshwater sharkWallago attu, Lucknow, India

Abstract

The fish host (Wallago attu) and monogenoid parasite (Thaparocleidus sp.) have been recorded during 2 years (2011 and 2012) to investigate intra/interspecific interactions among query species (T. sudhakari (Gusev, 1976) Lim, 1996; T. indicus (Kulkarni, 1969) Lim, 1996; T. gomtius (Jain, 1952) Lim, 1996; T. yogendraii Agrawal, 1981 and T. wallagonius Jain, 1952) in the light of parasitic worm burden, morphological and molecular data. Each species is highly host specific (oioxenous), with a specialized functional niche. Being niche specialists, they exhibit niche overlapping along with co-existence due to reproductive barrier. Furthermore, a molecular marker, affirming clear-cut genetic variation in spite of structural entities, provides evidence for infra-speciation as well as co-speciation.

Aggregation and negative interactions in low-diversity and unsaturated monogenean (Platyhelminthes) communities in Astyanax aeneus (Teleostei) populations in a neotropical river of Mexico

“…We found that monogeneans aggregate both at the population level and between species. These patterns have been previously described in ectoparasite communities of fish (Rohde et al, 1995; Morand et al, 1999; Simková et al, 2000, 2001; Agrawal et al, 2017). We observed that intraspecific aggregation (J) of the most abundant species increase with the intensity of the infection.…”

“…Simková et al (2000) did not find negative interactions, and based on the absence of negative correlations between the abundances among species pairs, argued that only when high population densities were achieved could competition play an important role. Agrawal et al (2017) evaluated 10 combinations of five species of congeneric monogeneans in 72 Wallago attu freshwater sharks in India, from which 10,920 monogeneans were recovered at an average of 151 individuals per fish examined. Populations of Thaparocleidus were aggregated (J > 0); they found that J positively correlated with the intensity of the infection.…”

“…We quantified the monogeneans’ intraspecific aggregation and interspecific aggregation following Ives (1988, 1991) as it has been applied to the analysis of fish ectoparasite communities by Morand et al (1999); Šimková et al, 2000, 2001, and Agrawal et al (2017). We calculated the parameter J for each monogenean taxa as an intraspecific aggregation measurement that quantifies the relative increase of conspecific competitors above the average number that a monogenean will find when it infects a new host (Ives, 1988), i.e., J is a measure of the proportional increase in the number of conspecific competitors that an individual monogenean experiences in a random distribution:J1=0.25em∑inn1in1i−1m1−m1m1=0.25emV1m1−1m1…”

“…Moreover, it has been demonstrated that aggregation is an important factor to determine local richness of monogeneans in fish populations (Morand et al, 1999; Simková et al, 2000, 2001; Agrawal et al, 2017). The host population represents a collection of patches of resources amongst which the parasites are heterogeneously distributed.…”

Competition from sea to mountain: Interactions and aggregation in low‐diversity monogenean and endohelminth communities in twospot livebearerPseudoxiphophorus bimaculatus(Teleostei: Poeciliidae) populations in a neotropical river

“…In species-rich parasitic communities that have high abundances, such as bird communities, both interspecific and intraspecific interactions among parasites are important forces that structure the community (e.g., Bush & Holmes, 1986;Stock & Holmes, 1988). In some fishes, mostly elasmobranchs, rich helminth communities have been described and interactions between species have been documented (e.g., Agrawal, Rajvanshi, & Asthana, 2017;Randhawa, 2012).…”