ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00633.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.The medial neurosecretory cells (MNC), corpus allatum (CA) and ovaries ofLucilia sericataMg. are quiescent in mature flies fed on a diet of sugar and water, but these tissues rapidly respond to the ingestion of a protein meal. The present study revealed that after oogenesis, virgin flies synthesized and stored neurosecretory material, but this activity declined as they grew older. At the same time, the CA, following a decrease in size during the latter stages of oogenesis, became enlarged again. This is interpreted as denoting synthesis but not release of CA hormone. In meat‐fed mated flies, cycles of oviposition and oogenesis were reflected in the rise and fall in activity of the MNC and CA. The MNC and CA of male flies also responded to the ingestion of a protein meal, and the activity of these tissues persisted for several days before it declined. The similar response of the MNC and CA in both males and females demonstrates the importance of a meat meal to reproduction in this species: in females it is required for oogenesis, but its ingestion by both sexes is necessary for overall reproductive succes

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00634.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.Eggs of the mosquitoCulex pipiens pipiensL. float vertically because a flexible corolla at the anterior (lower) pole has a hydrophilic lower surface and a hydrofuge upper surface. The corolla assumes different configurations in the egg raft; the surface forces operating on eggs are briefly analysed. The outer surface of the chorion is hydrofuge, but in eggs floating on water there is a jacket of water surrounding the egg in the spaces between the tubercles of the exochorion, below the meshwork connecting them. The humidity over natural water can be low enough to cause continuous evaporation from the jacket; water is replenished through openings within the lower surface of the corolla. The disposition of the corolla prevents the uptake of materials confined to the water surface outside, but the mechanism could concentrate solutes in the jacket, with possible deleterious consequences. Eggs are joined together by inter‐digitation of the regularly spaced tubercles. The behaviour by which the female assembles the egg raft is described in detail, explaining the form of the raft and the patterns in which eggs are packe

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00635.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.An actograph is described for recording the behaviour of small insects, by using a standing‐wave radar system in an enclosed metal cabinet. Experiments show that the system produces an output frequency dependent only on the speed of movement of the subject. By filtering the signal electrically into components below and above 5 Hz, walking and flying of adultMusca domesticacould be separately recorded. Each filter is followed by a level‐comparator with hysteresis. Activity causing signal to cross the hysteresis‐band is recorded as an event on a digital counter, and also integrated or summed to be displayed as a stepped‐integral or bar‐chart of total distance covered by the subject in each counting period. The energy‐density of the radar can be kept very low, so that possible influence on the subject is minimal. The detector is remote from the box containing the subject, giving great flexibility in container design, so that the apparatus is ideally suited to the study of environmen

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00636.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.The efficiency of the conversion of the digested food (ECD) (liver) during the growing period of the larva ofSarcophaga bullatawas determined. The values for ECD in four different determinations were 67.8, 69.1, 64.1 and 63.4%. These values are of the same order as ECD determined for some phytophagous caterpillars under the best conditions of food utilization, and seem to represent the highest values obtainable in a multicellular organism. It is concluded that such high efficiency rates have as prerequisites: fast growth in the larvae; and in the food, easy availability, ingestibility, and digestibility, high nutritional value, and reasonably high water content. Bacterial decomposition of the food during the test period appeared scarcely to influence the apparent ECD.

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00637.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.The motor output to the protractor and retractor mucles moving the coxa of the middle leg ofCarausius morosuswas recorded from the thoracic nerves during walking on a treadwheel. The leg movements on the wheel were generally similar to those found in free‐walking animals, but tripod coordination was relatively independent of period, and the coordination of the adult animal on the wheel was most closely related to that found in free‐walking first instars. The activity of a common inhibitor and four excitatory axons of the retractor and an excitatory axon of the protractor were followed for 850 steps (in six animals) to give a summary of the behaviour of the different units. The motor activity is less stereotyped than that previously reported for insects. There was strong reciprocity between the antagonists, but this was not directly correlated with the forward and backward movements of the legs. The first part of the stance phase of the leg was accompanied by a strong burst in the protractor nerve and relatively little retractor activity. This was followed by the main retractor burst which occupied the last 60% of the stance phase. The results are compared with motor output records of the locust and with earlier force‐plate measurements on the stick insect. It must be concluded that the mesothoracic leg initially resists forward movement of the body by the other legs during a typical walking

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00638.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.The responses of maleCeratitis capitata(Wiedemann) (Diptera; Tephritidae) to trimediure were investigated in a wind tunnel of novel design with disposable plastic walls. Trimediure was presented to the flies either in the form of a discrete ‘plume’ or uniformly dispersed in the air passing through the tunnel. The flies showed an increase in flight activity in response to the two forms of stimulation and performed a zig‐zag anemotactic flight in response to the plume, reminiscent of the behaviour of moths responding to a sex pheromone. They performed a straight, upwind, anemotactic response to the uniformly dispersed odour. The design of wind tunnel used in these tests was found to have several advantages: air flow and turbulence can be easily varied and the plastic walls can be changed to eliminate contamination pro

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00639.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.Allatectomy did not affect either food ingestion or midgut protease and invertase activity in adult femaleDysdercus cingulatusFabr., but ingestion of methoprene (juvenile hormone analogue) stimulated food consumption in the late instar caterpillars ofHyblaea pueraCramer. Implantation of brain to raise the insect's own level of brain neurosecretion also stimulated food ingestion inHyblaea.Caterpillars which either ingested methoprene or received brain‐implants showed higher levels of midgut amylase activity. However, no increase in amylase occurred after ingestion of methoprene or implantation of brain followed by starvation. A probable mechanism of hormonal influence on food ingestion and enzyme activity is discussed in the light of these result

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00640.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.The eggs ofSchistocerca gregaria(Orthoptera, Acrididae) incubated under natural conditions hatch only within a few of hours on either side of dawn. This gated hatching is controlled by a circadian clock that is phase set by the diel fluctuations in the temperature of the soil surrounding the eggs. There is a circadian fluctuation in haemolymph sugar concentration which is initiated at least 4 days before hatching. However, eggs hatch arrhythmically unless given cycled temperature incubation for at least 10 days of a 12–13‐day incubation. Increase in acetylcholine esterase content of the brain during the penultimate day suggests that increased hatching rhythmicity occurring at this time is the result of increased neural organization. Embryonic activity and respiration show no circadian rhythm but do provide confirmatory evidence of a quiescent phase prior to hatching. This quiescent phase is an integral part of gated hatching behavi

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00641.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.In femaleGryllus campestrisL., three functional types of ascending auditory intemeurones have been studied by recording from them extracellularly in the split cervical connectives using suction electrodes. Type 1 neurones are characterized by an optimal sensitivity to the carrier frequency of the species calling song (4–5 kHz). They copy the syllable and pause structure of the call at all intensities. The patterned spike discharge is observable at least 8 dB above absolute threshold. With suprathreshold stimulation, the neurones exhibit maximal responses (number of spikes/chirp) around the carrier frequency. The intensity response curves are approximately linear in the range of 40–90 dB SPL. The envelope of each syllable is reflected by a corresponding change in the firing rate, and syllable periods of 24ms and longer are resolved. This type can be considered as a neural correlate for phonotactic behaviour of the female where the syllable period has been found to be the most important temporal parameter. Type 2 neurones are most sensitive in the range of 4–6 and 11–13 kHz. They copy the syllable and pause structure of the species calling song at low and moderate intensities. However, the spikes invade the intersyllable pauses, when stimulated with the calling song at higher intensities (above 85 dB). This is particularly apparent at the onset of a chirp series. The slope of the intensity—response curve mimics that of type 1 units. The neurones cannot follow syllable periods shorter than 32 ms. Type 3 neurones differ from types 1 and 2 by a rather broad‐band sensitivity in the range of 3–16 kHz, and in copying the chirp as a whole. Even at low stimulus intensities, the intersyllable pauses are filled with spikes, and information about the syllable—pause structure is lost. Stimulation with suprathreshold intensities gives rise to a rather uniform, broad‐band response without distinctive peaks. The intensity—response curve is characterized by a higher absolute threshold, and by the reduction in the response magnitude starting above 70–80 dB. These units are not suitable for copying the calling song temporal structure in detail, but would indicate the chirping rhythm. Their strong response in the range of the species courtship song carrier frequency make them suitable to co

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00642.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY