scholarly journals Embryo-to-embryo communication facilitates synchronous hatching in grasshoppers

2021 ◽  
Vol 30 (2) ◽  
pp. 107-115
Author(s):  
Seiji Tanaka
Keyword(s):  
Group Size ◽  
Laboratory Experiments ◽  
Warm Period ◽  
Field Cricket ◽  
Continuous Illumination ◽  
Egg Hatching ◽  
Hatching Synchrony ◽  
Chorthippus Biguttulus ◽  
The Wire ◽  
Physical Signal

Synchronous hatching within single egg clutches is moderately common in locusts and other insects and can be mediated by vibrational stimuli generated by adjacent embryos. However, in non-locust grasshoppers, there has been little research on the patterns of egg hatching and the mechanisms controlling the time of hatching. In this study, the hatching patterns of six grasshoppers (Atractomorpha lata, Oxya yezoensis, Acrida cinerea, Chorthippus biguttulus, Gastrimargus marmoratus, and Oedaleus infernalis) were observed under various laboratory treatments. Under continuous illumination and a 25/30°C thermocycle, the eggs of these grasshoppers tended to hatch during the first half of the daily warm period. Eggs removed from egg pods and cultured at 30°C tended to hatch significantly earlier and more synchronously when kept in groups vs. singly. In general, eggs hatched earlier when egg group size was increased. Egg hatching was stimulated by hatched nymphs in some species, but not in others. In all species, two eggs separated by several millimeters on sand hatched less synchronously than those kept in contact with one another, but the hatching synchrony of similarly separated eggs was restored if they were connected by a piece of wire, suggesting that a physical signal transmitted through the wire facilitated synchronized hatching. In contrast, hatching times in the Emma field cricket, Teleogryllus emma, which lays single, isolated eggs, were not influenced by artificial clumping in laboratory experiments. These results are discussed and compared with the characteristics of other insects.

DIFFERENCES IN POST-DIAPAUSE THERMAL REQUIREMENTS FOR EGGS OF TWO RANGELAND GRASSHOPPERS

1987 ◽  
Vol 119 (7-8) ◽  
pp. 653-661 ◽  
Author(s):  
William P. Kemp ◽  
Norma E. Sánchez
Keyword(s):  
Laboratory Experiments ◽  
Field Observations ◽  
Degree Days ◽  
Egg Hatching ◽  
Grasshopper Species ◽  
Thermal Requirements ◽  
Diapause Development ◽  
Species Specific ◽  
Oviposition Sites ◽  
Accumulated Degree Days

AbstractA study was conducted to examine the springtime hatching characteristics of Melanoplus sanguinipes (F.) and Aulocara elliotti (Thomas) eggs on rangeland. Laboratory experiments showed that eggs of M. sanguinipes required fewer accumulated degree days (DD) to complete post-diapause development than those of A. elliotti at a constant temperature of 23.3°C. Springtime field observations revealed that A. elliotti nymphs emerged prior to or concurrent with M. sanguinipes. Additionally, results suggest that A. elliotti nymphs emerge over a shorter interval than M. sanguinipes. Much of the variation in springtime emergence could be attributed to species-specific oviposition sites, pod depth, and pod orientation that resulted in A. elliotti eggs accumulating heat more rapidly than M. sanguinipes eggs. Results help explain some of the variation found in egg hatching of these two grasshopper species on rangeland.

scholarly journals Seasonal and inter-species comparison of asymmetry in the genital system of some species of the oceanic copepod genus Metridia (Copepoda, Calanoida)

Crustaceana ◽  
2015 ◽  
Vol 88 (12-14) ◽  
pp. 1307-1321 ◽  
Author(s):  
Daichi Arima ◽  
Kohei Matsuno ◽  
Atsushi Yamaguchi ◽  
Takahiro Nobetsu ◽  
Ichiro Imai
Keyword(s):  
Laboratory Experiments ◽  
Okhotsk Sea ◽  
Calanoid Copepods ◽  
Species Comparison ◽  
Annual Average ◽  
Common Pattern ◽  
Egg Hatching ◽  
Global Oceans ◽  
Side Asymmetry ◽  
Hatching Rates

The seasonal and inter-annual changes in the asymmetry of female insemination and the male leg 5 of the planktonic calanoid copepods Metridia okhotensis and M. pacifica were investigated in the Okhotsk Sea. An inter-species comparison of both parameters was also carried out on seven Metridia species collected from oceans throughout the world. For M. okhotensis from the Okhotsk Sea, most of the females showed left-side insemination (annual average: 95.7%) and most of the males showed left-side asymmetry (99.7%) of the long inner process of the second exopodal segment in the fifth leg throughout the year. However, sympatric M. pacifica showed different ratios of asymmetry for female insemination and male morphotypes with a left : right = 1 : 2 ratio throughout the year. For the seven Metridia species from the global oceans treated in this study, ratios of asymmetry for female insemination and male morphotypes were correlated with each other. One-sided insemination (i.e., only left or only right insemination) was a common pattern for various Metridia species from global oceans, but their ratios varied by species. Previously, low hatching rates (29-68%) of eggs were reported for various Metridia spp. in laboratory experiments, but the reasons for these low rates were unclear. Because each spermatheca of Metridia spp. is connected to the oviduct on the same side, either left or right, this suggests that half of the eggs produced by unilaterally inseminated females remain unfertilized. The morphology of the genital structures and literature data of the egg hatching rates of Metridia spp. indicate that almost half of the eggs produced by females are not viable and are, thus, wasted.

Implications for comparability of laboratory experiments revealed in studies on the effects of population density on vigour in Coptotermes lacteus (Froggatt) and Nasutitermes exitiosus (Hill) (Isoptera: Rhinotermitidae & Termitidae)

1984 ◽  
Vol 74 (3) ◽  
pp. 477-485 ◽  
Author(s):  
M. Lenz ◽  
R. A. Barrett ◽  
E. R. Williams
Keyword(s):  
Group Size ◽  
Small Groups ◽  
Laboratory Experiments ◽  
Population Densities ◽  
Termite Species ◽  
The Usa ◽  
Optimal Population ◽  
Wood Consumption ◽  
The Impact ◽  
Comparability Of Results

AbstractThe vigour, i.e. survival and wood consumption, of groups of Coptotermes lacteus (Frogg.) and Nasutitermes exitiosus (Hill) was measured when termites were kept at different population densities by changing group size and/or volume of the holding container. A characteristic pattern emerged for subterranean termite species. At low population densities (<0·01 g termites/ml), performance improved with an increase in group size; at higher densities, it tended to decline. The impact of altering group size and container volume on termite vigour was most pronounced at low population densities; at higher population densities, performance tended to be more stable but declined markedly when termites became overcrowded. In most jar-type experiments on termites, especially those conducted in Europe and the USA, small groups of termites are housed in disproportionately large jars, resulting in very low, sub-optimal population densities. Suggestions are made for improvement in experimental design that would lead to an enhancement of the comparability of results from different laboratories.

scholarly journals Temporal variation in the reproductive success of Cacicus haemorrhous (Linnaeus) (Aves, Icterinae) in an Atlantic Forest reserve in Southeast Brazil

2005 ◽  
Vol 22 (2) ◽  
pp. 484-489 ◽  
Author(s):  
Charles Duca ◽  
Miguel Â. Marini
Keyword(s):  
Reproductive Success ◽  
Bird Species ◽  
Predation Rate ◽  
Reproductive Period ◽  
Reproductive Season ◽  
Egg Hatching ◽  
Forest Reserve ◽  
Hatching Synchrony ◽  
Minas Gerais State ◽  
Colonial Bird

For colonial bird species, egg hatching synchrony has been considered an important factor in their reproductive success. The Red-rumped Cacique, Cacicus haemorrhous (Linnaeus, 1766), is a Passeriformes species (Icterinae) that reproduces in colonies in which groups of females lay their eggs at different periods during the reproductive season. The objective of this study was to evaluate if there was a variation in the reproductive success among C. haemorrhous females groups that lay eggs in different periods along the reproductive season. A total of 192 nests from four colonies were monitored at Parque Estadual do Rio Doce, Minas Gerais state, Brazil, and used to calculate the nest survival probability in different periods (early and late) of the 2001 reproductive season. The results showed that females that reproduced at the beginning of the reproductive period had higher reproductive success than those that reproduced later. Predation was the main cause of nests loss (48,4%), and an increase in predation rate was observed as the reproductive period advanced.

scholarly journals Efficacy of Spiromesifen Against Greenhouse Whitefly (Homoptera: Aleyrodidae) on Strawberry

HortScience ◽  
2007 ◽  
Vol 42 (2) ◽  
pp. 285-288 ◽  
Author(s):  
J.L. Bi ◽  
N.C. Toscano
Keyword(s):  
Laboratory Experiments ◽  
Field Experiments ◽  
Resistance Management ◽  
Field Trials ◽  
Trialeurodes Vaporariorum ◽  
Fragaria Ananassa ◽  
Greenhouse Whitefly ◽  
Egg Hatching ◽  
Lower Toxicity ◽  
Chemical Class

Spiromesifen is a novel insecticide (belonging to the new chemical class of spirocyclic phenyl-substituted tetronic acids) with a unique mode of action. Laboratory and field experiments were conducted to test the efficacy of this insecticide against the greenhouse whitefly, Trialeurodes vaporariorum Westwood (Homoptera: Aleyrodidae) on strawberry, Fragaria ananassa (L.). Laboratory experiments showed that spiromesifen at 0.5 and 1.0 μg·mL−1 a.i. inhibited egg hatching by 80% and 100%, respectively, whereas at concentrations of 3.1, 3.0, and 10.0 μg·mL−1 a.i., this insecticide, respectively, killed 100% of the first, second, and third instar nymphs. Much lower toxicity to adults was observed. Field trials revealed that application of spiromesifen reduced the whitefly egg numbers by 61% to 80% from 2 to 3 weeks posttreatment in comparison with the pyriproxyfen treatment, whereas the application lowered the egg numbers by 34% to 73% from 2 to 5 weeks posttreatment compared with the buprofezin treatment. In comparison with pyriproxyfen treatment, spiromesifen application decreased the numbers of immature whiteflies by 29% to 92% from 1 to 6 weeks posttreatment. The effect of spiromesifen on reduction of immatures was similar to that of buprofezin. Also, the efficacy of spiromesifen on suppression of adult numbers was comparable to that of pyriproxyfen or buprofezin. Spiromesifen shows promise for inclusion in integrated greenhouse whitefly management programs and insecticide resistance management programs on strawberry.

scholarly journals Competition Reduces Response Times in Multiparty Conversation

2021 ◽  
Vol 12 ◽  
Author(s):  
Judith Holler ◽  
Phillip M. Alday ◽  
Caitlin Decuyper ◽  
Mareike Geiger ◽  
Kobin H. Kendrick ◽  
...  
Keyword(s):  
Group Size ◽  
Laboratory Experiments ◽  
Response Times ◽  
Corpus Analysis ◽  
Laboratory Studies ◽  
Significant Group ◽  
Transition Times ◽  
The Impact ◽  
Short Transition ◽  
Transition Type

Natural conversations are characterized by short transition times between turns. This holds in particular for multi-party conversations. The short turn transitions in everyday conversations contrast sharply with the much longer speech onset latencies observed in laboratory studies where speakers respond to spoken utterances. There are many factors that facilitate speech production in conversational compared to laboratory settings. Here we highlight one of them, the impact of competition for turns. In multi-party conversations, speakers often compete for turns. In quantitative corpus analyses of multi-party conversation, the fastest response determines the recorded turn transition time. In contrast, in dyadic conversations such competition for turns is much less likely to arise, and in laboratory experiments with individual participants it does not arise at all. Therefore, all responses tend to be recorded. Thus, competition for turns may reduce the recorded mean turn transition times in multi-party conversations for a simple statistical reason: slow responses are not included in the means. We report two studies illustrating this point. We first report the results of simulations showing how much the response times in a laboratory experiment would be reduced if, for each trial, instead of recording all responses, only the fastest responses of several participants responding independently on the trial were recorded. We then present results from a quantitative corpus analysis comparing turn transition times in dyadic and triadic conversations. There was no significant group size effect in question-response transition times, where the present speaker often selects the next one, thus reducing competition between speakers. But, as predicted, triads showed shorter turn transition times than dyads for the remaining turn transitions, where competition for the floor was more likely to arise. Together, these data show that turn transition times in conversation should be interpreted in the context of group size, turn transition type, and social setting.

Effects of temperature and photoperiod on the duration of hatching, swimming, and copepodid survival of the parasitic copepod Salmincola edwardsii

1993 ◽  
Vol 71 (5) ◽  
pp. 972-976 ◽  
Author(s):  
David C. Conley ◽  
Mark A. Curtis
Keyword(s):  
Water Temperature ◽  
Brook Trout ◽  
Laboratory Experiments ◽  
Hatching Success ◽  
Salvelinus Fontinalis ◽  
Parasitic Copepod ◽  
Swimming Activity ◽  
The Other ◽  
Egg Hatching ◽  
Effects Of Temperature

We conducted laboratory experiments to test whether various temperature and photoperiod regimes had any effect on the duration of egg hatching, swimming activity, and copepodid survival in the parasitic copepod Salmincola edwardsii, commonly found on brook trout (Salvelinus fontinalis). Pairs of egg sacs were removed from adult female copepods; one of each pair was exposed to a different photoperiod than the other, at the same temperature. Experiments were conducted at 8, 12, 16, and 20 °C. Temperature had a significant effect on the duration of copepodid swimming activity and survival, and the onset of egg sac hatching was directly related to increasing water temperature. However, hatching duration and hatching success were not affected by temperature over the range tested. Photoperiod had no effect on hatching duration, hatching success, swimming activity, or copepodid survival. Our findings indicate that S. edwardsii copepodids can swim and survive for more than 2 weeks; much longer than the 2 days customarily reported in the literature. This must be accounted for in the development of strategies to control transmission.

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