To look for the occurrence and the significance of brood care in social evolution, I reared six eusocial halictine bee species
in laboratory cages enabling the observation of intranest behaviour: Lasioglossum (Evylaeus) laticeps, L. (E.) pauxillum, L. (E.) nigripes, L. (E.) euboeensis, Halictus (Halictus) scabiosae and L. (E.) fulvicorne. All of them were subsocial, each mother caring for her brood. Brood cells were sealed after oviposition with earthen plugs;
they were then reopened, visited and closed again. These observations plus the reports in the literature on eleven eusocial
species indicate that seventeen species of eusocial halictine bees provide parental care, i.e. are subsocial. Brood care,
subsociality, is strongly associated with eusociality. To study reversal from eusociality to subsociality, I have reared the
non-eusocial form of two species within which there are or have been eusocial forms: Halictus (H.) rubicundus and Lasioglossum (E.) fratellum. They are secondarily solitary, having lost worker brood. However, both species still show brood care. This suggests that
in transitions to eusociality, brood care antedated eusociality. To further examine this issue I reared two truly solitary
species that are not derived from eusocial ancestors: Lasioglossum (E.) villosulum and L. (L.) quadrinotatum. Unlike secondarily solitary species, females of both these species close their brood cells after oviposition and ignore
their progeny thereafter. This association strongly suggests that the subsocial route with maternal brood care is the route
to eusociality in halictine bees. 相似文献
New, improved in vivo and in vitro approaches have led to a better understanding of the mechanisms that generate respiratory rhythm, which depends on a complex interaction between network and intrinsic membrane properties. The pre-Bötzinger complex in the ventrolateral medulla is particularly important for respiratory rhythm generation. This complex can be studied in isolation, and it contains all the known types of respiratory neurons that are now amenable to detailed cellular and molecular analyses. 相似文献
Anaphes victus Huber andAnaphes listronoti Huber (Hymenoptera: Mymaridae) are respectively solitary and gregarious egg parasitoids of the carrot weevil,Listronotus oregonensis (LeConte) (Coleoptera: Curculionidae). We made detailed ethograms of the oviposition behavior on unparasitized and parasitized hosts for the two species. We then compared the behavior of virgin and mated females for the oviposition of male and female progenies. The two species did not always oviposit after insertion of the ovipositor, but these punctures without oviposition could be readily differentiated from oviposition.A. victus oviposited only once by puncture, whileA. listronoti deposited one to three eggs during the same sequence. The variability of the duration of the various components was generally lower for a given female than between females. Two components, the abdominal vibrations and the pause, were significantly shorter in ovipositions that resulted in male progency for the two species. However, an important overlap in duration prevents using these differences to sex the progeny at oviposition. Virgin females of both species, although capable of producing only males, exhibited both behaviors. Parasitized hosts were recognized through internal and external markings that were used in host discrimination. 相似文献
Summary Host type choice and sex allocation were examined using the solitary parasitic waspDinarmus basalis (Pteromalidae, Hymenoptera) parasitizing larvae or pupae of the bean weevilCallosobruchus chinensis (Bruchidae, Coleoptera) within azuki beans (Vigna angularis). The wasps were offered two types of host; one was hard for the mother to lay eggs in, but was more beneficial for the offspring; the other was easy for the mother to lay eggs in, but was less beneficial for the offspring. The two types of host were one large host (17-day old host) in one bean and 6 small hosts (12-, or 13-day old hosts) in one bean. The same number of each host was presented at the same time to female wasps. The wasps accepted more 17-day old hosts than 12-day old hosts, and more 13-day old hosts than 17-day old hosts in each pair-wise choice experiment. The proportions of accepted host types were different from the proportions predicted by optimization models of random prey encounter with known or unknown prey densities. The wasps showed partial preference of host types. Incomplete information about prey densities, and about the costs and benefits of the two types of host may have generated the partial preference. Two predictions of host sizemodels, that (1) there should be a negative relationship between host size and offspring sex ratio (proportion of male offsprings), and (2) the sex ratio in each size host changes with the relative frequency of each size host utilized, were qualitatively supported. 相似文献
The development of tyrosine hydroxylase- and neuropeptide Y-immunoreactive cell bodies in the foetal rat brain was analyzed immunohistochemically using antibodies raised against tyrosine hydroxylase and neuropeptide Y. Possible co-existence of these two substance within the same neurones was investigated by comparison of adjacent sections.
In the ventral medulla oblongata, neurones containing both neuropeptide Y- and tyrosine hydroxylase-like immunoreactivity were demonstrable in and around the lateral reticular nucleus as early as the 17th day of gestation. The total number and the proportion of cells exhibiting this co-existence increased from this stage up to birth. In the nucleus of the solitary tract in the dorsal medulla oblongata, NPY-immunoreactive cells bodies were first visualized at day 13 of gestation. However, although tyrosine hydroxylase-immunoreactive cells could also be seen within the nucleus at this and later ages, they occupied a different, more caudal and medial part. Consequently, no neurones containing both neuropeptide Y and tyrosine hydroxylase were apparent up to the day of birth. Finally, in the locus coeruleus, tyrosine hydroxylase-immunoreactive neurones were also demonstrable at day 13 of gestation. In this case, however, no neuropeptide Y-immunoreactive somata could be seen in the nucleus until day 21.
The present study indicates that the existence of neuropeptide Y and tyrosine hydroxylase in co-containing neurones is not inextricably linked, and suggests that the factors controlling the synthesis of these two substances are not identical. 相似文献