Trait-mediated indirect interactions (TMII) can be as important as density-mediated indirect interactions. Here, we provide evidence for a novel trait-mediated cascade (where one TMII affects another TMII) and demonstrate that the mechanism consists of a predator eavesdropping on chemical signaling. Ants protect scale insects from predation by adult coccinellid beetles – the first TMII. However, parasitic phorid flies reduce ant foraging activity by 50% – the second TMII, providing a window of opportunity for female beetles to oviposit in high-quality microsites. Beetle larvae are protected from ant predation and benefit from living in patches with high scale densities. We demonstrate that female beetles can detect pheromones released by the ant when attacked by phorids, and that only females, and especially gravid females, are attracted to the ant pheromone. As ants reduce their movement when under attack by phorids, we conclude that phorids facilitate beetle oviposition, thus producing the TMII cascade.

Whether an ecological community is controlled from above or below remains a popular framework that continues generating interesting research questions and takes on especially important meaning in agroecosystems. We describe the regulation from above of three coffee herbivores, a leaf herbivore (the green coffee scale, Coccus viridis), a seed predator (the coffee berry borer, Hypothenemus hampei), and a plant pathogen (the coffee rust disease, caused by Hemelia vastatrix) by various natural enemies, emphasizing the remarkable complexity involved. We emphasize the intersection of this classical question of ecology with the burgeoning field of complex systems, including references to chaos, critical transitions, hysteresis, basin or boundary collision, and spatial self-organization, all aimed at the applied question of pest control in the coffee agroecosystem.

This paper provides a synthesis of the ecological impact of phorid fly parasitoids on ants. We find the most important impact of phorids on ants to be trait-mediated effects. Phorids diminish the foraging activity of ants, frequently reducing the number and average size of foragers and reducing the amount of food retrieved by a colony. However, ants' coping mechanisms include changing foraging site and time. Phorids can also affect competition, especially through changes in the ability of the host to win in exploitative competition. Factors such as microclimate, resource size, and habitat complexity interact with phorids to change their effect on competition. By being highly specific and attacking ants high in the competitive hierarchy, phorids can alter the linear nature of the competitive transitivity, and by reducing the number of foragers, they can change the discovery-dominance tradeoff that is observed in some ant communities. Trait-mediated effects of phorids also cascade to other trophic levels. As an example, we discuss the trait-mediated cascade of phorids on theAzteca instabilissystem in coffee. In this system, by reducing the foraging activity ofA. instabilis, phorids reduce the direct and indirect biological control impact of the ant in the coffee agroecosystem.

Most species are embedded in multi-interaction networks. Consequently, theories focusing on simple pair-wise interactions cannot predict ecological and/or evolutionary outcomes. This study explores how cascading higher-order interactions (HOIs) would affect the population dynamics of a focal species. Employing a system that involves a myrmecophylic beetle, a parasitic wasp that attacks the beetle, an ant, and a parasitic fly that attacks the ant, the study explores how none, one, and two HOIs affect the parasitism and the sex ratio of the beetle. We conducted mesocosm experiments to examine these HOIs on beetle survival and sex ratio and found that the 1st degree HOI does not change the beetle’s survival rate or sex ratio. However, the 2nd degree HOI significantly reduces the beetle’s survival rate and changes its sex ratio from even to strongly female-biased. We applied Bayes’ theorem to analyze the per capita survival probability of female vs. male beetles and suggested that the unexpected results might arise from complex eco-evolutionary dynamics involved with the 1st and 2nd degree HOIs. Field data suggested the HOIs significantly regulate the sex ratio of the beetle. As the same structure of HOIs appears in other systems, we believe the complexity associated with the 2nd degree HOI would be more common than known and deserve more scientific attention.

Resumen: Introducción. La insuficiencia velofaríngea es quizá la secuela más común de las técnicas de veloplastia realizadas para la corrección de las fisuras palatinas. A menudo la terapia fonoaudiológica se encuentra limitada, obteniéndose generalmente sólo resultados parciales. En estos casos la faringoplastia se presenta como el tratamiento de elección, existiendo diversas técnicas publicadas. Éstas, cualesquiera que sean, tienen en común la utilización de colgajos faríngeos que determinan una reducción del diámetro de la vía aérea superior con el consiguiente riesgo de generar un trastorno obstructivo del sueño. Objetivos. En el ánimo de obviar esta situación y simultáneamente alargar y dar competencia velopalatina, se ha diseñado una técnica quirúrgica que tiene por objetivo la reconstrucción morfofuncional velar o veloplastia funcional secundaria, inspirada en los principios de Delaire. Material y técnica quirúrgica. Presentamos nuestra experiencia basada en una serie de 15 casos tratados de esta nueva manera: se divide completamente el paladar blando, incindiendo sobre la línea media y exponiendo ambos hemivelos hasta la región retrouvular. En ese momento se busca e identifican las estructuras musculares remanentes, se separan del borde óseo palatino y de las mucosa nasal y bucal y se unen en una posición más posterior con las contralaterales en la línea media. Resultados. En nuestra experiencia se ha logrado el alargamiento velopalatino y la corrección o mejoramiento de rinolalias. En la evaluación de resultados hemos utilizado tanto el examen clínico fonoaudiológico como la aerofonoscopía con muy buenos resultados comparativos.