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Behavior of Colonial Orb‐weaving Spiders during a Solar Eclipse
Abstract
The behavior of colonial orb-weaving spiders (Metepeira incrassata) in tropical Veracruz, Mexico was studied during the total solar eclipse on July 11, 1991. Spiders behaved in a manner typical of daily activity until totality, when many began taking down webs. After solar reappearance, most spiders that had begun taking down webs rebuilt them. There was no significant difference in the overall activity patterns of spiders during totality across a range of colony sizes. Experimental illumination of part of a colony during totality altered web takedown behavior. While spiders in the darkness of totality began to take down webs, those spiders which were artificially illuminated did not. These observations suggest that the primary environmental cue responsible for the daily rhythm of web building behavior in this species is light level.
... Plants and animals use a wide variety of environmental cues for their biological activities, such as owering, migration, navigation, foraging, hibernation, aestivation among others [1][2][3][4][5][6][7][8] . Daylight and ambient temperature from the Sun are critical for many biological activities of organisms and behavior in many animals 4,[6][7]9 . ...
... Plants and animals use a wide variety of environmental cues for their biological activities, such as owering, migration, navigation, foraging, hibernation, aestivation among others [1][2][3][4][5][6][7][8] . Daylight and ambient temperature from the Sun are critical for many biological activities of organisms and behavior in many animals 4,[6][7]9 . Daylight is a major abiotic predictor of blooming in plants 10 . ...
Solar eclipse has remarkable effect on behavior of animals. South India experienced a 97% magnitude annular eclipse on December 26, 2019 during 0804 h-1104 h with the totality phase appeared during 0925–0930 h. We investigated the effect of this eclipse on foraging activity of bees to understand how a group of insects that rely the Sun, the sunlight, and the sun rays a lot for their navigation and vision behave to the eclipse. We opted to watch the bees in their foraging ground, and selected the natural flower populations of Cleome rutidosperma , Hygrophila schulli , Mimosa pudica , and Urena sinuata – the major bee-friendly plants – to record the visitor richness, visitation rate on the flowers on eclipse and non-eclipse days and during the hour of totality phase and partial phase of the eclipse. The plants received visits of nineteen and eleven species of bees, respectively on non-eclipse and eclipse days, but in the period of totality only three species of bees were active, but only in one population of C. rutidosperma . Visits of honey bees and stingless bees are affected most, but not that badly for solitary bees and carpenter bees. Bees, particularly the social bees use sun for navigation and deciphering information on food availability to fellow workers. The eclipse like for many other animals may hamper bees’ orientation, vision, and flight.
... Prior research lends some insight into this question, mainly via localized, anecdotal, or speciesspecific accounts during a past total solar eclipse. For example, orb-weaving spiders initiated their 15 nightly take-down of their web (4), but other arthropods exhibited little to no detectable response (5). During a 1932 eclipse, almost 500 reports across New England documented a range of responses, including 'subdued' domestic poultry, cattle heading towards their barn, and frogs beginning their dusk chorus (6). ...
On April 8th 2024, a total solar eclipse disrupted light-dark cycles for North American birds during the lead-up to spring reproduction. Compiling over 10,000 community observations and AI analyses of nearly 100,000 vocalizations, we found that bird behavior was significantly affected by these few minutes of unexpected afternoon darkness. More than half of wild bird species changed their biological rhythms, with many producing a dawn chorus in the aftermath of the eclipse. This natural experiment demonstrates the power of technology-enabled and public science projects to understand our natural world. Further, it underscores the power of light in structuring animal behavior: even when ‘night’ lasts for just four minutes, robust behavioral changes ensue.
... Solar eclipses present a rare and unique opportunity to study the solar corona and changes in the atmosphere prompted by the sudden decrease in the solar flux. Other lesser-known, and sometimes curious, phenomena include the dissipation of cumulus clouds (Trees et al., 2024), changes in the surface tension of water (Fuchs et al., 2019), spiders taking down their webs at the onset of totality (Uetz et al., 2010), and many others. Here, we investigate the potential effect of solar eclipses on the ozone layer. ...
Several publications have reported that total column ozone (TCO) may oscillate with an amplitude of up to 10 DU (Dobson units) during a solar eclipse, whereas other researchers have not seen evidence that an eclipse leads to variations in TCO beyond the typical natural variability. Here, we try to resolve these contradictions by measuring short-term variations (of seconds to minutes) in TCO using “global” (Sun and sky) and direct-Sun observations in the ultraviolet (UV) range with filter radiometers (GUVis-3511 and Microtops II®). Measurements were performed during three solar eclipses: the “Great American Eclipse” of 2024, which was observed in Mazatlán, Mexico, on 8 April 2024; a partial solar eclipse that took place in the United States on 14 October 2023 and was observed at Fort Collins, Colorado (40.57° N, 105.10° W); and a total solar eclipse that occurred in Antarctica on 4 December 2021 and was observed at Union Glacier (79.76° S, 82.84° W). The upper limits of the amplitude of oscillations in TCO observed at Mazatlán, Fort Collins, and Antarctica were 0.4 %, 0.3 %, and 0.03 %, respectively. The variability at all sites was within that observed during times not affected by an eclipse. The slightly larger variability at Mazatlán is due to cirrus clouds occurring throughout the day of the eclipse and the difficulty of separating changes in the ozone layer from cloud effects. These results support the conclusion that a solar eclipse does not lead to variations in TCO of more than ± 1.2 DU and that these variations are likely much lower, drawing into question reports of much larger oscillations. In addition to calculating TCO, we also present changes in the spectral irradiance and aerosol optical depth during eclipses and compare radiation levels observed during totality. The new results augment our understanding of the effect of a solar eclipse on the Earth's upper atmosphere.
... This was not true in the case of total solar eclipse (Galen et al., 2018). The complete cessation of bees' activity was attributed due to comparatively far lower visibility cues under dim light (Uetz et al., 1994). ...
Bees use sun’s position for navigation and thus a solar eclipse may affect this capability. Present study was conducted during partial solar eclipse on June 21, 2020 at Ludhiana, Punjab. Apis mellifera L foragers’ activity at the hive entrance was recorded through a digital bee counter. Bees’ activity increased normally, i.e. 771 and 823 bees/ 15 mins coming in and going out of the hive, respectively before the start of eclipsephase. At peak obscuration it decreased slightly but non-significantly. Changes in hive temperature andhumidity might have limited the recruitment of foragers. Hence, no peak activity was recorded duringpeak obscuration, which otherwise was recorded on ordinary days at 1345 hr.
... Az egyedek normális esetben reggel építik a hálójukat és este, sötétedéskor elbontják azt. A napfogyatkozás alatt a pókok többsége elkezdte lebontani a hálóját, majd miután kivilágosodott, a pókok megjavították a fogóhálót és folytatták nappali tevékenységüket (UETZ et al. 1994). Számos keresztespókféle kifejezetten csak éjszaka aktív (JONES et al. 2018). ...
Összefoglalás. Kronobiológiai áttekintésünkben bevezetjük az olvasót a biológiai ritmusok kutatásának rejtelmeibe. Munkánkban először a tudományterület fontosabb szabályait és szakkifejezéseit (terminus technikus-ait) ismertetjük, majd az élőlények különböző napszakokhoz történő alkalmazkodásának ökológiai jelentőségét és változatait tárgyaljuk. Ezután részletesebben bemutatjuk, hogy mit tudunk a pókok (Araneae) aktivitási ritmusairól és napszakos aktivitásáról, illetve, a csoport példáin keresztül azt is, hogy ezek a ritmusok milyen módszerekkel vizsgálhatók laboratóriumban és szabad-földön. Végezetül, alapozó jelleggel végigvesszük, hogy milyen módszerek/adatelemzési eljárások alkalmasak a különböző biológiai ritmusok értékelésére. ################################################## Abstract. This chronobiological ‘crash-course’ introduces the reader to the hidden world of biological rhythm research. Firstly, we review the major rules and technical terms of this discipline and we discuss the ecological aspects and types of adaptation to different temporal niches in animals. Then through the example of spiders (Araneae) we show in more detail what is known about the activity rhythms and diel activity of this group, and how these rhythms can be studied in the laboratory or under natural conditions. Finally, we briefly survey which methods/data analysis techniques can be used for proper evaluation of various biological rhythms.
... Anthropogenic disturbances such as cheering, applause, and other background noises may have induced additional anxiety in the animals, as seen in the threat display of three baboons toward a visitor group shortly prior to the onset of the eclipse. While efforts were made to minimize the confounding anthropogenic effects on our data by conducting baseline behavioral observations during the zoo's highest-capacity weekend, the increased human presence may have contributed to the behavioral responses of the animals (see reviews by [25,26]). One example is the grizzly bears waking during totality, which could be attributed to the meteorological phenomenon or to the cheering crowd during the event. ...
The infrequency of a total solar eclipse renders the event novel to those animals that experience its effects and, consequently, may induce anomalous behavioral responses. However, historical information on the responses of animals to eclipses is scant and often conflicting. In this study, we qualitatively document the responses of 17 vertebrate taxa (including mammals, birds, and reptiles) to the 2017 total solar eclipse as it passed over Riverbanks Zoo and Garden in Columbia, South Carolina. In the days leading up to the eclipse, several focal teams, each consisting of researchers, animal keepers, and student/zoo volunteers conducted baseline observations using a combination of continuous ad libitum and scan sampling of each animal during closely matched seasonal conditions. These same focal teams used the same protocol to observe the animals in the hours preceding, during, and immediately following the eclipse. Additionally, for one species—siamangs (Symphalangus syndactylus)—live video/audio capture was also employed throughout observations to capture behavior during vocalizations for subsequent quantitative analysis. Behavioral responses were classified into one or more of four overarching behavioral categories: normal (baseline), evening, apparent anxiety, and novel. Thirteen of seventeen observed taxa exhibited behaviors during the eclipse that differed from all other observation times, with the majority (8) of these animals engaging in behaviors associated with their evening or nighttime routines. The second predominant behavior was apparent anxiety, documented in five genera: baboons (Papio hamadryas), gorillas (Gorilla gorilla gorilla), giraffes (Giraffa cf. camelopardalis), flamingos (Phoenicopterus ruber), and lorikeets (Trichoglossus moluccanus and Trichoglossus haematodus). Novel behaviors characterized by an increase in otherwise nearly sedentary activity were observed only in the reptiles, the Galapagos tortoise (Chelonoidis nigra) and the Komodo dragon (Varanus komodoensis). While the anthropogenic influences on animal behaviors—particularly those relating to anxiety—cannot be discounted, these observations provide novel insight into the observed responses of a diverse vertebrate sample during a unique meteorological stimulus, insights that supplement the rare observations of behavior during this phenomenon for contextualizing future studies.
... Most eclipse research has focussed directly observable behaviour such as movement and foraging, e.g. changes in the marine community structure and movement alteration (Cadwallader and Eden 1977;Suter and Williams 1977;Jennings et al. 1998;Economou et al. 2008;Adhikari et al. 2018), greater production of phytoplankton (Adhikari et al. 2018) or the behavioural response of bees and other insects (Divan 1980;Uetz et al. 1994). A study during a solar eclipse in 1965 found that the movement of marine organisms resembled dawn and dusk behaviour (Backus, Clark, and Wing 1965). ...
Shifts in soundscapes often reflect diurnal patterns. In 2017 a total solar eclipse occurred in the US, resulting in a period of 3 h with the sun partially covered by the moon and 2 min of total darkness. We hypothesised this would create yet unmeasured and novel changes in different biophonic events. We placed automated recording units across an urban–rural gradient within the path of the total solar eclipse. We used generalised additive models to model and visualise acoustic shifts as a function of both time and per cent urban development. Biophony, a measure of the average frequency generated from biological sound, increased immediately before the period of the total solar eclipse and following the end of the eclipse, assuming the character of a dusk and dawn chorus. Other unique effects were observed, such as less anthrophony before totality. The total solar eclipse provided novel insight on temporal and spatial variation in soundscapes.
• Key policy inslights
• The ecological response to changes in a landscape can be measured over time and space using acoustic technology
• Landscape context must be considered when studying the biology of astrological events
• Generalized additive modeling allows a better understanding of non-linear and unique trends and consider the nested effect of location
Several publications have reported that total column ozone (TCO) may oscillate with an amplitude of up to 10 Dobson Units during a solar eclipse while other researchers have not seen evidence that an eclipse leads to variations in TCO beyond the typical natural variability. Here, we try to resolve these contradictions by measuring short-term (seconds to minutes) variations in TCO using “global” (Sun and sky) and direct-Sun observations in the ultraviolet (UV) range with filter radiometers (GUVis-3511 and Microtops). Measurements were performed during three solar eclipses: the "Great American Eclipse" of 2024, which was observed in Mazatlán, Mexico, on 8 April 2024; a partial solar eclipse taking place in the United States on 14 October 2023 and observed at Fort Collins, Colorado (40.57° N, 105.10° W); and a total solar eclipse occurring in Antarctica on 4 December 2021 and observed at Union Glacier (79.76° S, 82.84° W). The upper limit of the amplitude of oscillations in TCO observed at Mazatlán, Fort Collins, and Antarctica were 0.7 %, 0.3 %, and 0.03 %, respectively. The variability at all sites was within that observed during times not affected by an eclipse. The larger variability at Mazatlán is likely due to cirrus clouds occurring throughout the day of the eclipse and the difficulty of separating changes in the ozone layer from cloud effects. These results support the conclusion that a solar eclipse does not lead to variations in TCO of more than ± 2 Dobson Units and likely much less, drawing into question reports of much larger oscillations. In addition to calculating TCO, we also present changes in the spectral irradiance and aerosol optical depth during eclipses and compare radiation levels observed during totality. The new results augment our understanding of the effect of a solar eclipse on the Earth's upper atmosphere.
Solar eclipse has remarkable effect on behavior of animals. South India experienced a 97% magnitude annular eclipse on December 26, 2019 during 08:04–11:04 h with the totality phase appeared during 09:25–09:30 h. We investigated whether the foraging activity of the bees was limited by the eclipse, what bees are affected most, and which part of the eclipse was critical for bee activities to understand how a group of insects that rely the Sun, the sunlight, and the sun rays for their navigation and vision behaves to the eclipse. We opted to watch the bees in their foraging ground, and selected the natural flower populations of Cleome rutidosperma, Hygrophila schulli, Mimosa pudica, and Urena sinuata—some of the bee-friendly plants—to record the visitor richness and visitation rate on the flowers on eclipse and non-eclipse days and during the hour of totality phase and partial phase of the eclipse. Fewer flower-visiting species were recorded on the eclipse day than on the non-eclipse days, but in the period of totality, very few bee species were active, and limited their activity to only one population of C. rutidosperma. Visits of honey bees and stingless bees were affected most, but not that badly of solitary bees and carpenter bees. Bees, particularly the social bees use Sun for navigation and deciphering information on forage sources to fellow workers. The eclipse, like for many other animals, might hamper bees’ orientation, vision, and flight.
Metepeira atascadero, from desert/mesquite grassland habitat in north-central Mexico, shows a social organization in which spiders are predominantly solitary or in small groups of widely spaced individuals. Agonistic behavior patterns during conflicts over web sites show high levels of aggression and tend to escalate conflict. M. incrassata, from tropical rain-forest/agriculture habitats in the mountains above the Gulf of Mexico, live in groups of thousands of closely spaced individuals. Agonistic interactions of this species are settled quickly by signaling and tend not to escalate to more dangerous behaviors. These spiders show a high degree of tolerance of conspecifics, evidenced by their spatial organization, adjustment of web orientation, and cooperative construction of the communal web framework. Group foraging behavior observed in colonial Metepeira fits the predictions of risk-sensitive foraging theory. Since group foraging reduces variance in prey capture per individual, spiders tend to forage solitarily where prey availability is less than or equal to their needs, and in groups where prey availability is greater. These findings explain earlier observations of the tendency of Metepeira and a number of other orb-weaving spiders to build webs in groups exclusively in areas of high prey availability. Only in certain habitats or patches (those with superabundant prey) do spiders group webs together and reap the collective benefits of social foraging. Risk-sensitive foraging may be seen as a critical element in the evolution of coloniality in spiders. -from Authors
Effects of a total solar eclipse on fish have rarely been recorded. Three freshwater fish species — Amphipnous cuchia, Anabas testudineus and Colisa fasciata were studied during the past total solar eclipse on February 16, 1980. Behavioural studies pertaining chiefly to fish movement, fish breathing and colouration were made, and possible reasons for effects are discussed.
Seven major types of sampling for observational studies of social behavior have been found in the literature. These methods differ considerably in their suitability for providing unbiased data of various kinds. Below is a summary of the major recommended uses of each technique: In this paper, I have tried to point out the major strengths and weaknesses of each sampling method. Some methods are intrinsically biased with respect to many variables, others to fewer. In choosing a sampling method the main question is whether the procedure results in a biased sample of the variables under study. A method can produce a biased sample directly, as a result of intrinsic bias with respect to a study variable, or secondarily due to some degree of dependence (correlation) between the study variable and a directly-biased variable. In order to choose a sampling technique, the observer needs to consider carefully the characteristics of behavior and social interactions that are relevant to the study population and the research questions at hand. In most studies one will not have adequate empirical knowledge of the dependencies between relevant variables. Under the circumstances, the observer should avoid intrinsic biases to whatever extent possible, in particular those that direcly affect the variables under study. Finally, it will often be possible to use more than one sampling method in a study. Such samples can be taken successively or, under favorable conditions, even concurrently. For example, we have found it possible to take Instantaneous Samples of the identities and distances of nearest neighbors of a focal individual at five or ten minute intervals during Focal-Animal (behavior) Samples on that individual. Often during Focal-Animal Sampling one can also record All Occurrences of Some Behaviors, for the whole social group, for categories of conspicuous behavior, such as predation, intergroup contact, drinking, and so on. The extent to which concurrent multiple sampling is feasible will depend very much on the behavior categories and rate of occurrence, the observational conditions, etc. Where feasible, such multiple sampling can greatly aid in the efficient use of research time.
A captive group of chimpanzees, housed in an outdoor compound at the Yerkes Regional Primate Research Center, was observed during the annular solar eclipse of May 30, 1984. The behavior of each animal was recorded using an instantaneous scan-sampling technique (Altmann: Behaviour 49:227–265, 1974). Beginning 2 days prior to the eclipse and continuing through the day following the eclipse, data were collected from 1100 to 1300 hours daily. At 1214 hours on the day of the eclipse, when the sky began to darken and the temperature began to decrease, solitary females and females with infants moved to the top of a climbing structure. As the eclipse progressed, additional chimpanzees began to congregate on the climbing structure and to orient their bodies in the direction of the sun and moon. At 1223 hours, during the period of maximum eclipse, the animals continued to orient their bodies toward the sun and moon and to turn their faces upward. One juvenile stood upright and gestured in the direction of the sun and moon. Sunlight began to increase at 1225 hours, and as it became brighter, the animals began to descend from the climbing structure. The behaviors exhibited by the group during the period of maximum eclipse were not observed prior to or following the eclipse nor as darkness approached at normal, daily sunset. These data indicate that a solar eclipse, a rare and uncommon environmental event, can influence and modulate the behavior of chimpanzees.
Adult size and fecundity, total reproductive biomass, egg size, and spiderling size and resistance to desiccation were compared in three populations of the communal orb-weaving spider,Metepeira spinipes, in Mexico. In a desert population and in one from a moist tropical forest adult size, fecundity, and total reproductive biomass were similar, but were markedly smaller than in a climatologically intermediate agricultural habitat. Egg size and protein content were greater in the desert and agricultural habitats than in the moist forest, but spiderling size increased from desert to agricultural to moist forest populations. Desert spiderlings survived significantly longer than moist forest spiderlings at all humidity treatments over a 10% to 100% range. An explanation for these results is proposed based on apparent differences in energy allocation and expenditure which arise from the distinct climate, colony structure, and prey and space availability in the three habitats.