Use of an alarm pheromone against ants for gaining access to aphid/scale prey by the red velvet miteBalaustiumsp. (Erythraeidae) in a honeydew-rich environment

Abstract

SUMMARY This study shows that honeydew prompts arrestment and reduced activity, but not attraction, by the mite Balaustium sp. nr. putmani. When presented with short-range, two-choice bioassays, mites ceased their characteristic rapid crawling activity when they encountered honeydew-treated surfaces, resulting in them clustering around the honeydew. Approximately 80% of mites were retained by honeydew, with responses being independent of both mite life-history stage and source of honeydew (coccid scale insect or aphid). No obvious crawling movements or redirection of running path were made to the honeydew by the mites, implying the lack of any kind of attractant. Response of mites to single-sugar presentations of the main honeydew components – glucose, sucrose, fructose and trehalose – (0.001–0.1 mmol l–1) were inconsistent and failed to reproduce the arrestment/clustering associated with raw honeydew, suggesting that none of these sugars is an active arrestant ingredient. Formation of feeding clusters on honeydew does not contribute to enhancing water conservation by suppressing net transpiration (water loss) rates of individual mites as group size increases, indicating that the clustering is an artifact of arrestment. We hypothesize that release of neryl formate by the mites reduces negative interactions with the local ant species commonly associated with honeydew. We hypothesize that honeydew serves as: (1) a cue that facilitates discovery of scale/aphid prey; (2) a retainer on plants where these prey are present, signaling abundance and quality; and (3) an alternative and supplemental food source like that noted for other plant-inhabiting predatory mites. Neryl formate serves as an alarm pheromone and foul-tasting allomonal defense secretion that prevents predation of mites by ants that co-exist with aphid/scale insects in these honeydew-rich habitats.

Thermal thresholds of the predatory mite Balaustium hernandezi

“…nr. putmani , which aggregate at lower temperatures (Yoder et al , ). This behaviour is hypothesized to comprise a mechanism for alleviating water stress, and is observed in other acarine species such as Dermatophagoides farinae (Acari: Pyroglyphidae) and Alaskozetes antarcticus (Acari: Cryptostigmata) (Block & Convey, ; Glass et al , ; Benoit et al , ).…”

“…Several species within the genus Balaustium are reported as being fast moving (Cadogan & Laing, ; Yoder et al , , , ). The walking speed trials in the present study demonstrate that adult B. hernandezi can move significantly more quickly than larval B. hernandezi and T. urticae .…”

Ballı madde salgısı

“…Avcı nimflerinin, ballı madde ile bulaşık alanı, erginlerden daha hızlı bulduğu saptanmıştır. Yoder et al (2010), avcı Kırmızı kadife akarı (Balaustium sp., Acarina: Erythraeidae)'nın ballı madde ile bulaşık alanlarda çok sayıda olduğunu ve avını ararken ballı maddenin avını bulmakta kolaylık sağladığını kaydetmişlerdir. Aynı ortamdaki karınca ile avcı arasında negatif bir etkileşme olmadığını tespit etmiştir.…”