Exudate droplets incorporated on eggs by Raoiella indica Hirst female during oviposition may avoid the predation of Amblyseius largoensis (Muma)

• Published in: Experimental & applied acarology Vol. 93; no. 4; pp. 831 - 845
• Main Authors: Calvet, Érica C., de La Pava, Nataly, Oliveira, Ramony K. B., Favaris, Arodí P., Bento, José M. S., Gondim, Manoel G. C.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-12-2024; Springer Nature B.V
• Subjects: Amblyseius largoensis; Animal Ecology; Animal Genetics and Genomics; Animal Systematics/Taxonomy/Biogeography; Biomedical and Life Sciences; Chemical analysis; Consumption; Defensive behavior; Developmental stages; Droplets; Eggs; Embryogenesis; Entomology; Exudates; Exudation; Feeding behavior; Females; Host plants; Life Sciences; Oviposition; Predation; Predators; Raoiella indica; Setae; Egg defense; Chemical defense; Biological control; Tenuipalpidae; Parental care behavior
• ISSN: 0168-8162; 1572-9702; 1572-9702
• DOI: 10.1007/s10493-024-00964-x

Raoiella indica
Hirst has rapidly and widely spread throughout the New World since 2004, primarily infesting coconut palms and interacting with the predator
Amblyseius largoensis
(Muma). Although
A. largoensis
feeds on
R. indica
at all stages of development, it cannot naturally reduce its population to levels that do not impact the host plant.
Raoiella indica
possesses dorsal setae that secrete exudates during all post-embryonic developmental stages, and females have a behavior that deliberately deposits droplets on the freshly laid egg, possibly as a defense strategy against predation in vulnerable stages. In this context, we analyzed whether the presence or absence of droplets in
R. indica
eggs affects predation using
A. largoensis
as a biological model. Thus, we evaluated whether some biological and behavioral characteristics of
A. largoensis
could be affected by the consumption of
R. indica
egg masses washed or unwashed with water. Also, we performed a chemical analysis of the droplets exuded by
R. indica
and provided a description of the oviposition behavior of
R. indica
. The predator showed a higher consumption rate and preference for washed eggs. The results suggest that the exudate droplets have defensive functions, which are incorporated by the female onto the egg during oviposition and subsequently during a patrolling behavior, as they lose their effect after being washed with water. Although the droplets do not prevent the predator from feeding, they reduce the number of
R. indica
eggs consumed without affecting the growth of
A. largoensis
.