| Tetranychus urticae Koch(Acari: Tetranychidae)is an important pest mite on multiple vegetables,fruit trees,and ornamental plants,etc.Phytoseiulus persimilis Athias-Henriot(Acari: Phytoseiidae)is a specialist predator of spider mites,and is a successful predatory natural enemy widely used in biological control.Currently,P.persimilis is mainly mass reared on T.urticae,which is mass reared on its host plant(beans).To promote production efficiency and application of P.persimilis,it is necessary to develop artificial diet of T.urticae.In the present study,we investigated the structure of spider mite mouthparts,and its impact on feeding behavior and diet preference.We also determinated nutrition content of T.urticae and its host plant,and investigated the ingredients and their proportions for artificial diets of spider mites.In the first section,the appearance and ultrastructure of the mouthparts of three tetranychid mites: Tetranychus urticae,Tetranychus viennensis,and Panonychus ulmi,were observed with optical microscope and scanning electron microscope.For each of the three species,its stylophore appears to be two symmetric arms merged at the end and formed a reversed-U-shaped sac with longitudinal striates.The stylophores of T.urticae and T.viennensis are slender than that of P.ulmi.The lengths of stylets are 162.5?m,203.0?m,and 155.0?m,while the effective lengths are 110.8?m,149.6?m,and 107.1?m,for T.urticae,T.viennensis,and P.ulmi,respectively.Each spider mite has two stylets.When it is not feeding,its left and right stylets are separate.When feeding starts,the two stylets zip up and form a food channel and a salivary channel.Both T.urticae and T.viennensis have ridge-shaped flanges in their food channels,while that of P.ulmi was smooth inside.Dendrites were observed in the stylets of all three species.The rostrums of the three species all include rostral gutter,rostral fossette,and rostral cavity.The rostral fossette is trapezoid for T.urticae,heart-shaped for T.viennensis,and suborbicular for P.ulmi.There are two splayed channels,one on each side of the rostral cavity.The claws of the thumb-claws of the three species are all furcated,among which the distance between the furcation and the claw was the longest for T.urticae,followed by P.ulmi and T.viennensis.There is an ostiole on the base of each claw.The terminal sensillum of T.urticae is slender,while those of T.viennensis and P.ulmi are short cone-shaped,with the length-width ratio being 1.58,0.74 and 0.88 for the three species,respectively.The dorsal sensillum of T.urticae is fusiformed,while those of T.viennensis and P.ulmi aredendritic,with the length-width ratio being 2.19,3.19 and 2.71 for the three species,respectively.The setiform setae of the three species are all dendritic,with the length-width ratio being 5.67,6.18 and 5.15,respectively.We discovered that the terminal sensillum is actually silk spinneret of spider mites,with silks coming out from its top.The study compared the mouthpart structures among the three species in details,investigated the impact of mouthpart structures on diet preference and feeding behavior,and provided scientific bases for further investigations on artificial diet of T.urticae.In the second section,we determinated nutrition content of T.urticae and its host plant through high-performance liquid chromatography,which allows speculate the nutrition ingredients required by spider mites and the preferred proportions.Samples used in this study are: fresh bean leaves,bean leaves injured by T.urticae,satiated T.urticae,and starved T.urticae.All the four kinds of samples have high protein content,and low vitamin content(<100ng/mg).The total protein and saccharides content decreased by 46% and 34%,respectively,when fresh bean leaves were infested by spider mites for 1 week.In contrast,free amino acid content increased by 105%.Results of this experiment provided scientific bases to develop artificial diet formula of T.urticae.In the third section,we investigated potential packing material and content for artificial diet of T.urticae.We reared T.urticae on bean leaves covered with parafilm,and compared with those reared on fresh bean leaves.No significant differences between fecundity and survival of the two treatments were observed.We reared T.urticae on water solution of fresh bean leaves,and discovered that T.urticae survived 1 week longer than those only have water provided.We compared 18 formulas of artificial diet through orthogonal test.However,none of the formula appeared to be effective.The mean cumulative fecundity of T.urticae was 2 eggs,and mean survival was ca.20% for three days. |
PDF Full Text Request