Dermal secretion physiology in Metastriata ticks; thermoregulation in the lone star tick Amblyomma americanum

Ticks are blood feeding ectoparasites that transmit a wide range of pathogens. The lone star tick, Amblyomma americanum, is one of the most widely distributed ticks in the Midwest and Eastern United States. Lone star ticks, like most three-host ixodid ticks, can survive in harsh environments for extended periods without consuming a blood meal. Physiological mechanisms that allow them to survive during hot and dry season include thermal tolerance and water homeostasis. Large quantity of dermal fluid secretions induced by mechanical stimulation of tick legs has been described in metastriate ticks including Amblyomma. We hypothesize that a function of tick dermal secretion is similar to the sweating in large homeothermal animals. In this study, we found that a contact with a heat probe at 45oC can trigger dermal secretion. We demonstrated that dermal secretion plays a role in evaporative cooling when ticks are exposed to high temperature. We observed that direct contact to a heat probe for 5 seconds at ~ 52oC caused an exhaustive dermal secretion with ~ 4% loss of body weight and resulted in the lethality in 24-hour, indicating that the secretion is associated with significant costs of water loss. We identified type II dermal glands having paired two cells forming large glandular structures. The secretion is triggered by an injection of serotonin and the serotonin-mediated secretion was suppressed by a pretreatment of Ouabain, a Na/K-ATPase blocker, implying that the secretion is controlled by serotonin and the downstream Na/K-ATPase.

Pharmacophagy in green lacewings (Neuroptera: Chrysopidae:Chrysopaspp.)?

Green lacewings (Neuroptera: Chrysopidae) are voracious predators of aphids and other small, soft-bodied insects and mites. Earlier, we identified (1R,2S,5R,8R)-iridodial from wild males of the goldeneyed lacewing,Chrysopa oculataSay, which is released from thousands of microscopic dermal glands on the abdominal sterna. Iridodial-baited traps attractC. oculataand otherChrysopaspp. males into traps, while females come to the vicinity of, but do not usually enter traps. Despite their healthy appearance and normal fertility, laboratory-rearedC. oculatamales do not produce iridodial. Surprisingly, goldeneyed lacewing males caught alive in iridodial-baited traps attempt to eat the lure and, in Asia, males of otherChrysopaspecies reportedly eat the native plant,Actinidia polygama(Siebold & Zucc.) Maxim. (Actinidiaceae) to obtain the monoterpenoid, neomatatabiol. These observations suggest thatChrysopamales must sequester exogenous natural iridoids in order to produce iridodial; we investigated this phenomenon in laboratory feeding studies. Lacewing adult males fed various monoterpenes reduced carbonyls to alcohols and saturated double bonds, but did not convert these compounds to iridodial. Only males fed the common aphid sex pheromone component, (1R,4aS,7S,7aR)-nepetalactol, produced (1R,2S,5R,8R)-iridodial. Furthermore, althoughC. oculatamales fed the second common aphid sex pheromone component, (4aS,7S,7aR)-nepetalactone, did not produce iridodial, they did convert ∾75% of this compound to the corresponding dihydronepetalactone, and wildC. oculatamales collected in early spring contained traces of this dihydronepetalactone. These findings are consistent with the hypothesis thatChrysopamales feed on oviparae (the late-season pheromone producing stage of aphids) to obtain nepetalactol as a precursor to iridodial. In the spring, however, wildC. oculatamales produce less iridodial than do males collected later in the season. Therefore, we further hypothesize that AsianChrysopaeatA. polygamato obtain iridoid precursors in order to make their pheromone, and that other iridoid-producing plants elsewhere in the world must be similarly usurped by maleChrysopaspecies to sequester pheromone precursors.

Pharmacophagy in green lacewings (Neuroptera: Chrysopidae: Chrysopa spp.)?

Green lacewings (Neuroptera: Chrysopidae) are voracious predators of aphids and other small, soft-bodied insects and mites. Earlier, we identified the first lacewing pheromone from field-collected males of the goldeneyed lacewing, Chrysopa oculata Say; (1R,2S,5R,8R)-iridodial is released from thousands of microscopic dermal glands on the abdominal sterna of males, along with comparable amounts of nonanal, nonanol and nonanoic acid. Iridodial-baited traps attract C. oculata and other Chrysopa spp. males into traps, while females come to the vicinity of, but do not usually enter baited traps. Despite their healthy appearance, normal fertility and usual amounts of C9 compounds, laboratory-reared C. oculata males do not produce iridodial. However, we observed that goldeneyed lacewing males caught alive in iridodial-baited traps sometimes try to eat the lure, and in Asia Chrysopa spp. males reportedly eat the native plant, Actinidia polygama (Siebold & Zucc.) Maxim. (Actinidiaceae) to obtain the iridoid, neomatatabiol. These observations prompted us to investigate why laboratory-reared Chrysopa green lacewings do not produce iridodial. Lacewing adult males fed various monoterpenes reduced carbonyls to alcohols and saturated double bonds, but did not convert these compounds to iridodial. Males fed the bicyclic iridoid aphid pheromone component, (4aS,7S,7aR)-nepetalactone, converted ~75% to dihydronepetalactone, but did not produce iridodial; however, wild C. oculata males collected in May often contained traces of dihydronepetalactone. On the other hand, adult males fed the second common aphid pheromone component, (1R,4aS,7S,7aR)-nepetalactol, converted this compound to iridodial. In California the peak late-season attraction of green lacewings to nepetalactol (the lactone is unattractive) occurs at least a month earlier than the peak in aphid oviparae (the pheromone producing morph of aphids), consistent with the hypothesis that Chrysopa males feed on oviparae to obtain nepetalactol as a precursor to iridodial. Adult males from laboratory-reared C. oculata larvae fed nepetalactol failed to produce iridodial, and wild C. oculata males collected early in the spring produce less iridodial than males collected later in the season. Therefore, we further hypothesize that Asian Chrysopa eat A. polygama to obtain iridoid precursors in order to make their pheromone, and that other iridoid-producing plants elsewhere in the world must be similarly usurped by male Chrysopa species to sequester pheromone precursors. Whether or not sequestration of iridodial precursors from oviparae and/or iridoid-containing plants is truly the explanation for lack of pheromone in laboratory-reared Chrysopa awaits further research .

Pharmacophagy in green lacewings (Neuroptera: Chrysopidae: Chrysopa spp.)?

Green lacewings (Neuroptera: Chrysopidae) are voracious predators of aphids and other small, soft-bodied insects and mites. Earlier, we identified the first lacewing pheromone from field-collected males of the goldeneyed lacewing, Chrysopa oculata Say; (1R,2S,5R,8R)-iridodial is released from thousands of microscopic dermal glands on the abdominal sterna of males, along with comparable amounts of nonanal, nonanol and nonanoic acid. Iridodial-baited traps attract C. oculata and other Chrysopa spp. males into traps, while females come to the vicinity of, but do not usually enter baited traps. Despite their healthy appearance, normal fertility and usual amounts of C9 compounds, laboratory-reared C. oculata males do not produce iridodial. However, we observed that goldeneyed lacewing males caught alive in iridodial-baited traps sometimes try to eat the lure, and in Asia Chrysopa spp. males reportedly eat the native plant, Actinidia polygama (Siebold & Zucc.) Maxim. (Actinidiaceae) to obtain the iridoid, neomatatabiol. These observations prompted us to investigate why laboratory-reared Chrysopa green lacewings do not produce iridodial. Lacewing adult males fed various monoterpenes reduced carbonyls to alcohols and saturated double bonds, but did not convert these compounds to iridodial. Males fed the bicyclic iridoid aphid pheromone component, (4aS,7S,7aR)-nepetalactone, converted ~75% to dihydronepetalactone, but did not produce iridodial; however, wild C. oculata males collected in May often contained traces of dihydronepetalactone. On the other hand, adult males fed the second common aphid pheromone component, (1R,4aS,7S,7aR)-nepetalactol, converted this compound to iridodial. In California the peak late-season attraction of green lacewings to nepetalactol (the lactone is unattractive) occurs at least a month earlier than the peak in aphid oviparae (the pheromone producing morph of aphids), consistent with the hypothesis that Chrysopa males feed on oviparae to obtain nepetalactol as a precursor to iridodial. Adult males from laboratory-reared C. oculata larvae fed nepetalactol failed to produce iridodial, and wild C. oculata males collected early in the spring produce less iridodial than males collected later in the season. Therefore, we further hypothesize that Asian Chrysopa eat A. polygama to obtain iridoid precursors in order to make their pheromone, and that other iridoid-producing plants elsewhere in the world must be similarly usurped by male Chrysopa species to sequester pheromone precursors. Whether or not sequestration of iridodial precursors from oviparae and/or iridoid-containing plants is truly the explanation for lack of pheromone in laboratory-reared Chrysopa awaits further research .

Pharmacophagy in green lacewings (Neuroptera: Chrysopidae: Chrysopa spp.)?

Green lacewings (Neuroptera: Chrysopidae) are voracious predators of aphids and other small, soft-bodied insects and mites. Earlier, we identified the first lacewing pheromone from field-collected males of the goldeneyed lacewing, Chrysopa oculata Say; (1R,2S,5R,8R)-iridodial is released from thousands of microscopic dermal glands on the abdominal sternum of males, along with comparable amounts of nonanal, nonanol and nonanoic acid. Iridodial-baited traps attract C. oculata and other Chrysopa spp. males into traps, while females come to the vicinity of, but do not usually enter baited traps. Despite their healthy appearance, normal fertility and usual amounts of C9 compounds, laboratory-reared C. oculata males do not produce iridodial. However, we observed that goldeneyed lacewing males caught alive in iridodial-baited traps sometimes try to eat the lure, and in Asia Chrysopa spp. males reportedly eat the native plant, Actinidia polygama (Siebold & Zucc.) Maxim. (Actinidiaceae) to obtain the iridoid, neomatatabiol. These observations prompted us to investigate why laboratory-reared Chrysopa green lacewings do not produce iridodial. Lacewing adult males fed various monoterpenes reduced carbonyls to alcohols and saturated double bonds, but did not convert these compounds to iridodial. Males fed the bicyclic iridoid aphid pheromone component, (4aS,7S,7aR)-nepetalactone, converted ~75% to dihydronepetalactone, but did not produce iridodial; however, wild C. oculata males collected in May often contained traces of dihydronepetalactone. On the other hand, adult males fed the second common aphid pheromone component, (1R,4aS,7S,7aR)-nepetalactol, converted this compound to iridodial. In California the peak late-season attraction of green lacewings to nepetalactol (the lactone is unattractive) occurs at least a month earlier than the peak in aphid oviparae (the pheromone producing morph of aphids), consistent with the hypothesis that Chrysopa males feed on oviparae to obtain nepetalactol as a precursor to iridodial. Adult males from laboratory-reared C. oculata larvae fed nepetalactol failed to produce iridodial, and wild C. oculata males collected early in the spring produce less iridodial than males collected later in the season. Therefore, we further hypothesize that Asian Chrysopa eat A. polygama to obtain iridoid precursors in order to make their pheromone, and that other iridoid-producing plants elsewhere in the world must be similarly usurped by male Chrysopa species to sequester pheromone precursors. Whether or not sequestration of iridodial precursors from oviparae and/or iridoid-containing plants is truly the explanation for lack of pheromone in laboratory-reared Chrysopa awaits further research .