Dynamics of periodical cicada chorus centers (Homoptera: Cicadidae:Magicicada)

Mating aggregations of three species of periodical cicadas were monitored during the emergence of Brood XIX at a 16-ha study site in northwest Arkansas, May–June 1985. Magicicada tredecassiniappeared first and formed the most choruses. M. tredecimand M. tredeculachoruses formed next, and M. tredeculachoruses outnumbered those of M. tredecim.Of the 268 choruses seen, 84% were composed of M. tredecassini. M. tredecassiniwere often found chorusing in the same trees with the other two species. Such multispecies mating aggregations apparently are unique to periodical cicadas. Choruses were dynamic with respect to their locations and durations. Initially, choruses were located near areas of high cicada emergence densities. One week later, cicadas chorused in trees throughout the forest and at the forest edge. Many choruses were seen only once at a location. Although cicadas chorused for almost 4 weeks, individual choruses persisted only approximately 8 days, on average. Sound intensities under chorus centers ranged from 50 to 80 dh and were correlated with arena sizes during times of peak chorus activity. No distinct habitat preferences of the three species were observed, however, the tree species used by chorusing cicadas differed among the species.     

Eicosanoids mediate control of thermoregulatory sweating in the cicada,Tibicen dealbatus (Insecta: Homoptera)

Cicadas prevent body temperature from exceeding tolerable levels by a combination of behavioral responses and sweating. Sweating is activated when body temperature reaches a critical set-point temperature. We investigated control of sweating in the cicada, Tibicen dealbatus, by chemically manipulating biosynthesis of prostaglandins and other eicosanoids. Injecting prostaglandins in amounts equal to those that induce behavioral fever in scorpions and crustaceans resulted in only a small increase in set-point temperature. Blocking prostaglandin biosynthesis with cyclo-oxygenase inhibitors such as aspirin produced significant changes in set-point temperature, confirming that prostaglandins are involved in control of sweating. However, the effect of cyclo-oxygenase inhibitors was not the opposite of the effect of prostaglandins. Instead, the effect of cyclo-oxygenase inhibitors depended strongly on the value of setpoint temperature prior to treatment. Results of biochemical manipulations of other steps in eicosanoid biosynthetic pathways corroborated the results of cyclo-oxygenase inhibition and indicated that eicosanoids other than prostaglandins may be involved in control of body temperature in normothermic T. dealbatus. The effect of cyclo-oxygenase inhibitors on a given set-point temperature depended on the ambient temperature experienced by cicadas during the experiment. Surprisingly, cicadas exposed to ambient temperatures 40°C delayed activation of sweating until body temperature exceeded values normally recorded from T. dealbatus in the field. Control of body temperature in normothermic cicadas is thus complex, involving inputs from body temperature sensors, ambient temperature sensors, and at least two cyclo-oxygenase-dependent regulatory pathways.Abbreviations PUFA polyunsatured fatty acid(s) - T _a ambient temperature - T _b body temperature - T _set set-point of body temperature for activation of sweating     

Ambient temperature and sound power of cicada calling songs (Hemiptera: Cicadidae: Tibicina)

Abstract.  Male cicadas produce a loud calling song that attracts females at long range. In some cases, ambient temperature has been shown to have an effect on the temporal structure of this acoustic signal. Here, a positive correlation is reported for the first time between the ambient temperature and the sound power of the calling song. This relationship is illustrated in three species of the Palaearctic genus Tibicina : Tibicina corsica fairmairei Boulard, Tibicina garricola Boulard and Tibicina tomentosa Olivier. It is suggested that the males thermoregulate behaviourally. The minimal ambient temperature range that the Tibicina species need to call is 22–24 °C. The effect of ambient temperature on calling song power is assumed to be the result of thermal effects in the response of the acoustic system (i.e. muscle activity of the acoustic system being temperature-dependent). Inter-individual and interspecific differences in calling song power are interpreted in the general context of the Tibicina sound behaviour.     

Identification of acoustic stimuli that mediate sexual behavior inDrosophila busckii (Diptera: Drosophilidae)

We have shown that D. busckiimales and females, unlike other drosophilids that have been analyzed in this regard, court and copulate as well in relatively dim red light as they do in bright white light. We have also shown that males and females of this species flutter their wings during courtship and that wing fluttering in both sexes is associated with acoustic stimuli. Wingless males perform vigorous courtship but are incapable of mating, suggesting that females must perceive male song to be receptive to copulation. When they are tested with normal males, wingless females stimulate vigorous courtship, but their copulation frequencies are significantly lower than winged females. This observation suggests that perception of the female's song by either or both sexes facilitates mating.     

Diurnal activity, temperature responses and endothermy in three South American cicadas (Homoptera: Cicadidae: Dorisiana bonaerensis, Quesada gigas and Fidicina mannifera)

1. 1. Measurements of body temperature (T_b) in the field demonstrated that endothermic cicadas regulate T_b by behavioral mechanisms as well as by endogenous heat production.

2. 2. The T_b of endothermically active cicadas without access to exogenous heat is approximately the same as the T_b of basking cicadas.

3. 3. Dorisiana bonaerensis (Berg) and Quesada gigas (Olivier) raise T_b in the field with the heat produced in flight.

4. 4. The thermal responses of a particular species are related to its activity patterns and habitat.

5. 5. Endothermy in cicadas may serve to uncouple reproductive behavior from environmental constraints; to circumvent possible thermoregulatory problems; to permit the utilization of habitats unavailable to strictly ectothermic cicadas; to reduce predation; and to optimize broadcast coverage and sound transmission.

     

Cicada acoustic communication: potential sound partitioning in a multispecies community from Mexico (Hemiptera: Cicadomorpha: Cicadidae)

Multispecies cicada communities in neotropical rainforests produce a complex and intense acoustic environment. In a fragment of a Mexican rainforest (Veracruz, Mexico), a cicada community at the end of the dry season consisted of nine species ( Daza montezuma; Pacarina schumanni; Miranha imbellis; Dorisiana sutori; Fidicinoides picea; Fidicinoides pronoe; Quesada gigas; one species of the genus Neocicada and one uncaught canopy species). Seven of the nine species formed dense choruses at dawn and at dusk. Each species showed preferences in the height of calling sites. Males of the species were solitary or gregarious, and followed a 'call-fly' or a 'call-stay' calling strategy. Acoustic signals of each species had particular time and frequency patterns. All these specific features appear to separate the nine species acoustically and lead to a partitioning of the acoustic environment. The acoustic partitioning might decrease the risk of heterospecific courting and mating.© 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 75 , 379–394.     

Comparative thermoregulation of sympatric endothermic and ectothermic cicadas (Homoptera: Cicadidae: Tibicen winnemanna and Tibicen chloromerus)

Measurements of body temperature in the field demonstrated that endothermic cicadas regulate body temperature by behavioral mechanisms as well as by endogenous heat production. Regression analysis suggests both endothermic and ectothermic species are thermoregulating. Body temperature of endothermically active cicadas without access to exogenous heat is approximately the same as the body temperature of basking cicadas. Tibicen winnemanna (Davis) raises body temperature in the field with the heat produced in flight or through the activation of the flight musculature without the act of flight. T. chloromerus (Walker) uses solar radiation to elevate body temperature to the level necessary for activity. The thermal responses of each species are related to its activity patterns with minimum flight temperature and shade-seeking temperatures significantly lower in the endothermic T. winnemanna. Heat torpor temperature appears to be related to the environment rather than behavior pattern. Endothermy in cicadas may serve to uncouple reproductive behavior from environmental constraints; to circumvent possible thermoregulatory problems; to permit the utilization of habitats unavailable to strictly ectothermic cicadas; to reduce predation; to optimize broadcast coverage and sound transmission; and to decrease possible acoustic interference. Accepted: 25 March 2000     

Evaporative cooling and endothermy in the 13-year periodical cicada,Magicicada tredecem (Homoptera: Cicadidae)

Summary The thermobiology of a cicada, Magicicada tredecem, from a warm, high humidity environment was investigated. Thoracic temperature (T_th) of M. tredecem in the field was strongly dependent on, and consistently higher than, ambient temperature (T_am), averaging 33.0±0.19°C on warm sunny days (T_am=28–29°C, rh=60–75%). Laboratory studies documented cuticle water fluxes high enough ( 5mg · cm^–2 · h^–1 in dry air at 40°C) to result in a significant degree of passive evaporative cooling, but the ability of M. tredecem to actively facilitate evaporative water loss during thermal stress is comparatively limited: water loss rates (WLR) of live M. tredecem at 40°C (dry air) were only 35–45% greater than those of dead cicadas. The limited ability of M. tredecem to facilitate transcuticular WLR is associated with limited surface distribution of the cuticular ducts through which water is actively extruded during evaporative cooling. In the laboratory, active extrusion of water had no appreciable effect on T_th, demonstrating that evaporative cooling was due largely to passive water flux through the highly permeable cuticle. The location of the abdominal pore tracts is such that extrusion of water through the ducts may preferentially cool the heart and perhaps other abdominal tissues. Long-term climatological data indicate that M. tredecem rarely encounters T_am levels high enough (i.e., above its apparent T_th setpoint of 34–35°C) to require evaporative cooling. Inactive M. tredecem can endothermically increase T_th. An hypothesis is proposed to account for the diversity of body temperature setpoints in cicadas.Abbreviations rh relative humidity - SOT standard operating temperature - T _am ambient temperature - T _b body temperature - T _sp body temperature setpoint - T _th thoracic temperature - TWF transcuticular water flux - WLR water loss rate     

Infectivity of resting spores of Massospora cicadina (Entomophthorales: Entomophthoraceae), an entomopathogenic fungus of periodical cicadas (Magicicada spp.) (Homoptera: Cicadidae)

Progeny of eastern oyster, Crassostrea virginica, introduced into France in 1992, were reared in IFREMER facilities to test their growth performances. During the summer of 1993, sporadic mass mortalities (80-90%) occurred among C. virginica spat reared in the IFREMER laboratories in La Tremblade (Charente Maritime, France) and Bouin (Vendée, France). Affected oysters presented mantle retraction and deposition of an anomalous conchiolin layer on the inner surface of the shell. The incidence of oysters with gross signs exceeded 80%. No obvious pathogen was identified in soft tissues by histology and transmission electron microscopy (TEM). However, histological examination showed the presence of anomalous basophilic round structures, 0.5-1 microm in diameter, in gill and mantle connective tissues. These extracellular Feulgen-negative structures reacted positively with the von Kossa stain. TEM examination on mantle and gill samples in diseased spat showed that the basophilic bodies consisted of concentric deposits of an amorphous substance interpreted as containing calcium. These observations may indicate that the mineralization process in spat shells was disturbed without exact determination of the cause. Based on the similarities of the gross signs to those reported in juvenile eastern oysters in the United States, we believe that the cause of the mortalities observed in France was probably the Juvenile Oyster Disease. Moreover, we report for the first time the detection of anomalous amorphous structures in gill and mantle connective tissues associated with mortalities and deposition of an anomalous conchioloin layer on the inner shell surface in C. virginica spat.     

温度和LED光源对夹竹桃天蛾幼虫行为的影响

为探明温度和光照对夹竹桃天蛾幼虫行为的影响,在实验室条件下观察了5个温度(20、25、30、35和40℃)和5个不同波段的LED光源(红光620—625、黄光580—585、蓝光465—467、绿光520—523和白光460—465 nm)下夹竹桃天蛾幼虫的行为,结果表明:(1)温度对夹竹桃天蛾幼虫行为发生频率和时间分配有影响,各实验温度下休息时间分配均较多。(2)LED光源对夹竹桃天蛾幼虫行为发生频率和时间分配亦有影响,绿色LED光源下的瞭望行为发生频率最高,取食时间分配也最多。(3)各种行为的昼夜节律性因光照条件不同而异。爬行、瞭望、取食和休息行为在16L∶8D光照条件下均显示了昼夜节律性,16L∶8R光照条件下的行为(除第2天的瞭望行为外)具有类似的节律性,爬行行为在黄光处理下保持了节律性,而在蓝光和绿光处理各种行为节律性不明显。这些研究结果揭示了光温对夹竹桃天蛾幼虫行为的影响因温度高低和LED光源颜色(波段)及自身行为种类不同而异。     

Body temperature in captive long-beaked echidnas (Zaglossus bartoni)

The routine occurrence of both short-term (daily) and long-term torpor (hibernation) in short-beaked echidnas, but not platypus, raises questions about the third monotreme genus, New Guinea's Zaglossus. We measured body temperatures (T(b)) with implanted data loggers over three and a half years in two captive Zaglossus bartoni at Taronga Zoo, Sydney. The modal T(b) of both long-beaks was 31 degrees C, similar to non-hibernating short-beaked echidnas, Tachyglossus aculeatus, in the wild (30-32 degrees C) and to platypus (32 degrees C), suggesting that this is characteristic of normothermic monotremes. T(b) cycled daily, usually over 2-4 degrees C. There were some departures from this pattern to suggest periods of inactivity but nothing to indicate the occurrence of long-term torpor. In contrast, two short-beaked echidnas monitored concurrently in the same pen showed extended periods of low T(b) in the cooler months (hibernation) and short periods of torpor at any time of the year, as they do in the wild. Whether torpor or hibernation occurs in Zaglossus in the wild or in juveniles remains unknown. However, given that the environment in this study was conducive to hibernation in short-beaks, which do not easily enter torpor in captivity, and their large size, we think that torpor in wild adult Zaglossus is unlikely.     

The acoustic ecology of an Amazonian bird assemblage: the role of allometry,competition and environmental filtering in the acoustic structure

Communication among birds constitutes the foundation of social interactions, and acoustic signals should evolve based on their efficiency to convey information. We examined the acoustic signals of an Amazonian bird assemblage by testing whether vocal allometry was the main driver in song evolution. We expected the acoustic parameters of the songs to follow general allometric rules, as the size of the vocal apparatus limits the vibration capacity of the syrinx. We tested whether smaller species use lower than expected frequencies due to environmental filtering by examining deviations from allometric relationships. Alternatively, small species could use higher than expected frequencies as a consequence of competitive processes that promote the use of vacant portions of the acoustic spectrum. We recorded birdsongs between 2013 and 2018 and measured three spectral parameters: the dominant frequency (FDOM), the minimum fundamental frequency (FFMIN) and the maximum fundamental frequency (FFMAX). We created an allometric model based on the acoustic pattern of the larger species and used it to predict the frequencies of the smaller species. We compared the frequency values expected by allometry with the observed parameters of the avian assemblage. We found that FDOM and FFMIN were higher than expected by allometry alone, supporting competition structuring in the acoustic ecology of the assemblage. The successful insertion of many species into the acoustic space is the result of long processes of natural selection, with our data highlighting the importance of competition in the vocal structuring of the community.     

Reproductive isolation inProkelisia planthoppers (Homoptera: Delphacidae): Acoustic differentiation and hybridization failure

Males and females of Prokelisia marginata (Van Duzee) and Prokelisia dolusWilson communicate through substrate-transmitted vibrations. The acoustic signals (attraction and courtship calls) of these planthoppers are effective in mate location, attraction, and mate choice. Attraction calls are structurally distinct for both species and differ in pulse type, pulse repetition rate, and pulse duration. Using playback of prerecorded calls, individuals discriminated between conspecific and heterospecific signals. Depending on the sex and species, response calls were produced three to eight times more frequently to conspecifics than to heterospecifics. However, acoustic signals alone did not explain reproductive isolation and hybridization failure in these two congeners. Some heterospecific pairs called, courted, and attempted to join genitalia, but no connections were successful and no progeny were produced. Thus, acoustic behavior is not a guaranteed premating isolating mechanism in no-choice situations. Other courtship behaviors and possibly morphological differences in genitalia also contributed to their isolation. Females displayed a variety of rejection behaviors to conspecific and heterospecific males, suggesting that sexual selection (female choice), in addition to species recognition, may be an important force in the evolution of the acoustic signals of planthoppers. Although signal structure was not dependent on wing form (planthoppers exhibit wing dimorphism), the age when females first began to call was related to wing form. Brachypterous (flightless) females of both species began calling early in adult life (day 2), whereas macropterous (migratory) females began calling later in adult life (day 6). This pattern is consistent with the oogenesis-flight syndrome, in which reproductive maturity is delayed until after migration occurs.     

Testing drivers of acoustic divergence in cicadas (Cicadidae: Tettigettalna)

Divergence in acoustic signals may have a crucial role in the speciation process of animals that rely on sound for intra-specific recognition and mate attraction. The acoustic adaptation hypothesis (AAH) postulates that signals should diverge according to the physical properties of the signalling environment. To be efficient, signals should maximize transmission and decrease degradation. To test which drivers of divergence exert the most influence in a speciose group of insects, we used a phylogenetic approach to the evolution of acoustic signals in the cicada genus Tettigettalna, investigating the relationship between acoustic traits (and their mode of evolution) and body size, climate and micro-/macro-habitat usage. Different traits showed different evolutionary paths. While acoustic divergence was generally independent of phylogenetic history, some temporal variables’ divergence was associated with genetic drift. We found support for ecological adaptation at the temporal but not the spectral level. Temporal patterns are correlated with micro- and macro-habitat usage and temperature stochasticity in ways that run against the AAH predictions, degrading signals more easily. These traits are likely to have evolved as an anti-predator strategy in conspicuous environments and low-density populations. Our results support a role of ecological selection, not excluding a likely role of sexual selection in the evolution of Tettigettalna calling songs, which should be further investigated in an integrative approach.     

Body temperature and behaviour of golden hamsters (Mesocricetus auratus) and ground squirrels (Spermophilus tridecemlineatus) in a thermal gradient

Golden hamsters and thirteen-lined ground squirrels were maintained individually in a thermal gradient (14°C to 33°C) for several weeks under a 14L: 10D light-dark cycle. Animals of both species showed robust daily rhythms of body temperature and locomotor activity with acrophases consistent with the habits of the species (diurnal acrophases in the diurnal squirrels and nocturnal acrophases in the nocturnal hamsters). Hamsters showed a robust daily rhythm of temperature selection 180° out of phase with the rhythms of body temperature and locomotor activity. Squirrels did not show a daily rhythm of temperature selection. These results raise the hypothesis that a daily rhythm of temperature selection is exhibited by nocturnal but not by diurnal endotherms.     

Red-winged blackbird predation on periodical cicadas (Cicadidae: Magicicada spp.): bird behavior and cicada responses

Summary Predation by red-winged blackbirds Agelaius phoeniceus L. on 13-year periodical cicadas (Magicicada spp.) and reactions by periodical cicadas to predators were studied during emergence of Brood XIX during summer of 1985 in northwestern Arkansas (USA). Emergences of periodical cicadas are classic examples of predator satiation due to high local densities of cicadas and birds are the major predators of adult periodical cicadas. Reactions of periodical cicadas to predators were assessed by recording behaviors exhibited by cicadas when approached in trees by a human hand during the 3-week period of peak adult densitics. Most male cicadas made a noise in association with escape behaviors when approached, and 50% of the females, which are silent, attempted escape behaviors. Observations of predation attempts on cicadas by red-winged blackbirds were made during the period of peak predation pressure. Red-winged blackbirds spent less time searching for cicadas over that 2-week period of increasing predation pressure, and became increasingly efficient at capturing cicadas. Handling time of cicadas by red-winged blackbirds increased by about 20 seconds over that period, as blackbirds spent more time consuming female cicadas. The flysquawk response, used only by male cicadas, was effective in deterring red-winged blackbirds; only 5% of the attacks by blackbirds were successful when that behavior was exhibited. All cicadas that remained motionless and silent when approached by blackbirds were captured and consumed. Because females remained inactive when approached more often than did males, blackbirds may have consumed more female cicadas. Changes that appeared in reactions of preiodical cicadas to the model predator and to the attacks of blackbirds reflect both changes in the sex ratio of the cicada populations and changes in behaviors of cicadas associated with mating and egg laying. The loud noise made by male periodical cicadas at mating centers did not appear to deter predation by blackbirds. Changes in the behavior of blackbirds that appeared to be in association with greater predation on female periodical cicadas relates directly to aspects of foraging theory, particularly predictions concerning more selective foraging during periods of abundant food resources.     

Effect of Manipulations on the Host Selection Behavior of Sitobion avenae (Homoptera: Aphididae)

The study of aphid host selection and feeding behavior is difficult because aphids have to penetrate the plant to reach their feeding site, phloem tissue. The activity of the stylets, salivation or food intake, can not be observed externally and requires an indirect visualization technique such as the Electric Penetration Graph (EPG). The plant selection behavior of Sitobion avenae on potato varied depending on whether an ethological or EPG method was used to study it. A similar variation did not occur with Myzus persicae or Rhopalosiphum padi. The application of water-based silver conductive paint onto the thorax, as normally used for EPG, or onto the abdomen of Sitobion avenae alates resulted in increased duration and frequency of probing compared to results from ethological observations. Our results indicated that EPG manipulations might have different effects on different species of aphids and that a comparison of EPG and ethological data is required to confirm that the EPG method does not bias aphid feeding behavior.