ABSTRACT
Maternal care is critically important for the survival of offspring in various animals. Spiders in the family Lycosidae are known for their hunting ability and maternal care behaviors. Predation on newly hatched spiderlings (pulli) by mother spiders decreases when they come into contact, and they carry the pulli on their dorsal surface. However, the factors inducing maternal care in lycosid spiders have not been elucidated. In this study, we investigated maternal care in Pardosa pseudoannulata (Araneae, Lycosidae) females. We proposed that the physical interaction between pulli and mother spiders induces maternal care via m-aminophenylacetylene (m-A), a novel regulator of maternal care. The presence of pulli on the dorsal abdomen of non-mother spiders suppressed pulli predation and increased the pulli-carrying rate, and the absence of pulli on the mother spiders increased pulli predation and decreased the pulli-carrying rate. The compound m-A was abundant in mother spiders, and it could be induced in non-mother spiders when they carried pulli. The topical application of m-A to non-mother spiders and m-A injection decreased pulli predation and increased the pulli-carrying rate, respectively; these findings indicate that m-A in both internal tissues and the integument is required for the induction of maternal care behavior, and the interaction between pulli and females induces the production of m-A. In-depth study of the regulatory mechanism of maternal care will enhance our understanding of spider biology and behavior.
ABSTRACT
Cys-loop ligand-gated channels mediate neurotransmission in insects and are receptors for many insecticides. Some insecticides acting on cysLGIC also have lethal effects on non-targeting organisms, but the mechanism of this negative effect is unclear due to information absence. The identification and analysis of cysLGIC family in Pardosa pseudoannulata, a pond wolf spider, can deepen the understanding of insecticides for natural enemy safety. Thirty-four cysLGIC genes were identified in P. pseudoannulata genome, including nicotinic acetylcholine receptors, γ-aminobutyric acid gated chloride channels, glutamate-gated chloride channels, histamine-gated chloride channels, and pH-sensitive chloride channels. The expansion of GABACls and HisCls accounts for the large number of cysLGICs in P. pseudoannulata, and the alternative splicing events in nAChR and RDL subunits enriched the diversity of the superfamily. Most cysLGIC genes show the highest expression in brain and lowest expression in the early-egg sac stage. Variable residues (R81, V83, R135, N137, F190, and W197) in P. pseudoannulata nAChR ß subunits and critical differences in α6 subunit TM4 region compared with insects would apply for the insensitivity to neonicotinoids and spinosyn. In contrast, avermectin and dieldrin may be lethal to P. pseudoannulata due to the similar drugs binding sites in GluCls compared with insects. These findings will provide a valuable clue for natural enemy protection and environmentally friendly insecticide development.
