Intraguild predation between phytoseiid mite species might not be so common

Abstract

It is widely acknowledged that intraguild predation (IGP) occurs frequently between species of phytoseiid mites. However, in the presence of a shared resource many species of phytoseiid mites considerably reduce, or even cease, predation on each other. That being the case, IGP would then be minimal, or non-existent, and its theoretical effects on communities negligible. The aim of this work was two-fold. On the one hand, we aimed at determining the occurrence of IGP between two species of phytoseiid mites that inhabit avocado agro-ecosystems (Euseius stipulatus and E. scutalis) while considering the influence of abiotic conditions. On the other hand, we aimed at evaluating the occurrence of IGP between species of phytoseiid mites through a literature search of studies to determine whether methodologies and results in these papers supported the extended idea of IGP being widespread in the Phytoseiidae family. Our results suggested that in the presence of the shared resource predation on the IG-prey was negligible and both species seem to forage preferentially on pollen. Therefore, the interaction that most likely drives the dynamics of these two species in the field is exploitative resource competition. The literature search revealed that caution should be taken when assuming that IGP between phytoseiid mites is widespread, because only few works used experimental set ups with the adequate array of treatments allowing to assess whether IG-predators fed or not on both the IG-prey and the shared resource.

Efectos de las condiciones abióticas sobre las interacciones entre tres depredadores de Tetranychus urticae con distintos hábitos alimenticios

“…To sum up, our data are indicative that Climate Change may actually disrupt existing natural regulation of T. urticae in clementines, same as other authors have described for similar systems (Montserrat et al 2013a, b;Guzmán et al 2016b). In order to examine all the possible interactions between the three phytoseiids above and T. urticae, further laboratory research under controlled conditions could help explaining the results obtained and better predicting future outcomes.…”

“…Existe una elevada diversidad de estudios que predicen los efectos que originan las condiciones de cambio climático sobre: la biodiversidad de distintas especies (Garcia et al 2014), cadenas tróficas (Sentis et al 2015), enemigos naturales (Thomson et al 2010), modelos de adaptación de especies (Valladares et al 2014), relaciones presa-depredador en el control biológico de conservación (Schmitz and Barton 2014) y una elevada cantidad de estudios de gran interés sobre futuras predicciones del calentamiento global. Además, varios autores están estudiando el efecto del alimento alternativo sobre la abundancia de los depredadores y el control de plagas en condiciones extremas (González-Fernández et al, 2009;Guzmán et al, 2016b;Montserrat et al, 2013aMontserrat et al, , 2013b.…”

“…urticae, como ya han descrito otros autores en sistemas similares al nuestro (Montserrat et al 2013a, b;Guzmán et al 2016b). En nuestro experimento de campo, se evaluó la regulación de T. urticae ejercida por los tres depredadores fitoseidos estudiados en distintas situaciones (cadena trófica, competencia y efectos prioritarios), durante primavera (aproximación de las condiciones óptimas) y verano (aproximación de las condiciones de cambio climático).…”

How to evaluate the potential occurrence of intraguild predation

“…However, laboratory experiments on IGP are frequently only short-term because of experimental logistics (Briggs and Borer 2005; Janssen et al 2006). Such short-term experiments can only provide qualitative information about whether or not two species are potentially able to engage in IGP (Guzmán et al 2016). Nevertheless, long-term dynamical predictions are commonly inferred from these short-term experiments and consequently may lead to inaccurate interpretations (Brown et al 2001; Hastings 2004; Briggs and Borer 2005).…”

“…Nevertheless, long-term dynamical predictions are commonly inferred from these short-term experiments and consequently may lead to inaccurate interpretations (Brown et al 2001; Hastings 2004; Briggs and Borer 2005). Recently, Guzmán et al (2016) introduced another relevant concern about the methods used in these short-term experiments, that is, there is no consensus regarding criteria to evaluate the occurrence of IGP, and thus, methodological differences may underlie apparent inconsistencies among studies. These authors proposed criteria to evaluate IGP in predatory mites, but these criteria are easily generalized to other arthropod systems, e.g., aquatic arthropods (Wissinger and McGrady 1993; Crumrine 2005), arthropod pests (Rosenheim et al 1995) and spiders (Polis and McCormick 1986).…”