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opencc-zeroFeb 2020View details →

Emergent social cohesion for coping with community disruptions in disasters

<p>Social cohesion is an important determinant of community well-being, especially in times of distress such as disasters. This study investigates the phenomena of emergent social cohesion, which is characterized by abrupt, temporary, and extensive social ties with the goal of sharing and receiving information regarding a particular event influencing a community. In the context of disasters, emergent social cohesion, enabled by social media usage, could play a significant role in improving the ability of communities to cope with disruptions in recent disasters. In this study, we employed a network reticulation framework to examine the underlying mechanisms influencing emergent social cohesion in online social media while communities cope with disaster-induced disruptions. We analyzed neighborhood-tagged social media data (social media data whose users are tagged by neighborhoods) in Houston during Hurricane Harvey to characterize four modalities of network reticulation (i.e., enactment, activation, reticulation, and performance) giving rise to emergent social cohesion. Our results show that, unlike regular social cohesion, communication history and physical proximity do not significantly affect emergent social cohesion. The results also indicate that weak social ties play an important role in bridging different social network communities, and hence reinforce emergent social cohesion. The findings can inform public officials, emergency managers and decision-makers regarding the important role of neighborhood-tagged social media, as a new form of community infrastructure, for improving the ability of communities to cope with disaster disruptions through enhanced emergent social cohesion.</p>

opencc-zeroDec 2017View details →

Data from: Coping with the climate: cuticular hydrocarbon acclimation of ants under constant and fluctuating conditions

Terrestrial arthropods achieve waterproofing by a layer of cuticular hydrocarbons (CHCs). At the same time, CHCs also serve as communication signals. To maintain waterproofing under different climate conditions, insects adjust the chemical composition of their CHC layer, but this may affect the communication via CHC. The detailed acclimatory changes of CHCs and how these influence their physical properties are still unknown. Here, we studied acclimation in two closely related ant species with distinct CHC profiles, Myrmica rubra and Myrmica ruginodis, in response to constant or fluctuating temperature and humidity regimes. We measured how acclimation affected CHC composition and viscosity, and the ants' drought survival. In both species, CHC composition showed strong, predictable responses to temperature regimes. Warm-acclimated individuals had higher proportions of linear alkanes, and less methyl-branched or unsaturated CHCs. These changes coincided with higher solid content and viscosity of CHCs in warm-acclimated ants. Temperature fluctuation caused effects similar to constant-cool conditions in M. rubra, but led to entirely different profiles in M. ruginodis, suggesting that fluctuating and constant conditions pose very different challenges. Acclimation to dry conditions led to higher absolute amounts of CHCs, which increased the ants' drought survival, whereas temperature acclimation did not. Hence, the temperature-induced CHC changes cannot be explained by the need for waterproofing alone. While these changes could be non-adaptive, we propose that they serve to maintain a constant CHC viscosity, which may be essential for communication and other functions.

opencc-zeroSep 2019View details →

Data from: Stress coping and evolution of aerobic exercise performance: corticosterone levels in voles from a selection experiment

The locomotor performance achieved in a challenging situation depends not only on physiological limitations, such as the aerobic exercise capacity, but also on behavioral characteristics, such as adequate stress coping. The stress response is mediated largely by the hypothalamic-pituitary-adrenal (HPA) axis, through modulated release of glucocorticoids. We used a unique experimental evolution model system to test a hypothesis that evolution of an increased aerobic exercise performance can be facilitated by modification of the glucocorticoid-related stress coping mechanisms. Bank voles (Myodes glareolus) from "aerobic" (A) lines, selected for 22 generations for high maximum swim-induced rate of oxygen consumption (VO2swim), achieved a 64% higher VO2swim than those from unselected, control (C) lines. The temporal pattern of exercise during the swimming trial also evolved, and the A-line voles achieved VO2swim later in the course of the trial, which indicates a modification in the stress response characteristics. Both VO2swim and the average metabolic rate measured during the trial tended to increase with baseline corticosterone level, and decreased with the post-exercise level. Thus, increased baseline corticosterone level promotes high metabolic performance, but a high corticosterone response to swimming acts as an inhibitor rather than stimulator of intense activity. However, neither of the corticosterone traits differed between the A-selected and control lines. Thus, the experiment did not provide evidence that evolution of increased aerobic performance is facilitated by modification of the glucocorticoid levels. The results, however, do not exclude a possibility that other aspects of the HPA axis function evolved in response to the selection.

opencc-zeroDec 2014View details →

Data from: Cope's rule and the universal scaling law of ornament complexity

Luxuriant, bushy antlers, bizarre crests, and huge, twisting horns and tusks are conventionally understood as products of sexual selection. This view stems from both direct observation and from the empirical finding that the size of these structures grows faster than body size (i.e., ornament size shows positive allometry). We contend that the familiar evolutionary increase in the complexity of ornaments over time in many animal clades is decoupled from ornament size evolution. Increased body size comes with extended growth. Since growth scales to the quarter power of body size, we predicted that ornament complexity should scale according to the quarter power law as well, irrespective of the role of sexual selection in the evolution and function of the ornament. To test this hypothesis, we selected three clades (ammonites, deer, and ceratopsian dinosaurs) whose species bore ornaments that differ in terms of the importance of sexual selection to their evolution. We found that the exponent of the regression of ornament complexity to body size is the same for the three groups and is statistically indistinguishable from 0.25. We suggest that the evolution of ornament complexity is a by-product of Cope's rule. We argue that although sexual selection may control size in most ornaments, it does not influence their shape.

opencc-zeroMar 2020View details →

Coping with the commute: behavioural responses to wind conditions in a foraging seabird

Movement is a necessary yet energetically expensive process for motile animals. Yet how individuals modify their behaviour to take advantage of environmental conditions and hence optimise energetic costs during movement remains poorly understood. This is especially true for animals that move through environments where they cannot easily be observed. We examined the behaviour during commuting flights of black-legged kittiwakes Rissa tridactyla breeding on Middleton Island, Alaska in relation to wind conditions they face. By simultaneously deploying GPS and accelerometer devices on incubating birds we were able to quantify the timing, destination, course and speed of flights during commutes to foraging patches, as well as how wing beat frequency and strength relate to flight speeds. We found that kittiwakes did not preferentially fly in certain wind conditions. However, once in the air they exhibited plasticity by increasing their air speed (the speed at which they fly relative to the wind) when travelling into headwinds and decreasing their air speed when flying with tailwinds. This strategy maximises flight range, whereby the greatest air distance is covered per unit of energy expenditure. Furthermore, we identified a biomechanical link behind this behaviour: that to achieve these changes in flight speeds, kittiwakes altered their wing beat strength, but not wing beat frequency. Using this information, we demonstrate that the cost of flying into a headwind outweighs the benefit of flying with a tailwind of equivalent speed, therefore exploiting a tailwind when commuting to a foraging patch would not be beneficial if having to return in the same direction with the same conditions. Our findings suggest that extrinsic factors, such as prey availability, have a more influential role in determining when and where birds fly during foraging trips than do wind conditions. However, once flying, kittiwakes exhibit behavioural plasticity to minimise transport costs.

opencc-zeroDec 2014View details →

Data from: High-nature-value grasslands have the capacity to cope with nutrient impoverishment induced by mowing and livestock grazing

1. Management of high-nature-value (HNV) grasslands follows agri-environmental schemes across large areas of Europe. Long-term agreements and restrictions of fertilizers cause soil nutrient impoverishment, but remarkably this quite often does not reduce biomass production. Therefore, we tested how species-rich vegetation copes with nutrient impoverishment under the most frequently used treatments, that is summer mowing and livestock grazing. 2. During 2011–2012 we studied, simultaneously, plant species composition, soil and biomass chemical properties in two equally designed experiments where mowing, grazing or leaving fallow have been applied since 2004. We asked whether soil-based (Corg : Ntot, plant-available P and K) and plant-based measures (N : P, N : K, K : P ratios and N-, P-, K-nutrition indices) indicate the same pattern of nutrient limitation as the observed productivity gradient. 3. Seven years of management application resulted in the lowest plant-available P under grazing and the lowest plant-available K under mowing, but neither grazed nor mown plots produced less biomass than fallow ones. Grazing supported dominance of grasses while mowing that of non-leguminous forbs. 4. Projection of nutrition indices to a common framework with nutrient ratios suggests that critical thresholds for diagnosis of nutrient limitation are a function of N deficiency. At biomass production of 2 t ha−1 a N-nutrition index of 50 yielded threshold N : P = 14·0; hence, all our treatments with N : P of 9·9–12·5 should be N limited. 5. Inspecting the productivity gradient separately for each management, we found only soil Corg : Ntot negatively related to biomass production in mown plots indicating N limitation. However in grazed plots, positive association of biomass production with plant-available P and negative with biomass N : P and N : K suggested PK co-limitation. 6. Synthesis and applications. Mowing and grazing induced different patterns of soil nutrient impoverishment and nutrient limitation, but they did not reduce biomass production of high-nature-value grasslands. Non-leguminous forbs prevailing under mowing precluded shortage of P, while grasses dominating under grazing efficiently captured N. We recommend designing agri-environmental measures that will encourage alternating mowing and grazing. This should promote coexistence of multiple forbs and grasses, balance nutrient limitation and ensure stable biomass production under future low-input scenarios.

opencc-zeroDec 2015View details →

Data from: How individual Montagu's Harriers cope with Moreau's Paradox during the Sahelian winter

Hundreds of millions of Afro-Palaearctic migrants winter in the Sahel, a semi-arid belt south of the Sahara desert, where they experience deteriorating ecological conditions during their overwintering stay and have to prepare for spring migration when conditions are worst. This well-known phenomenon was first described by R.E. Moreau and is known ever since as Moreau's Paradox. However, empirical evidence of the deteriorating seasonal ecological conditions is limited and little is known on how birds respond. Montagu's Harriers Circus pygargus spend 6 months of the year in their wintering areas in the Sahel. Within the wintering season, birds move gradually to the south, visiting several distinct sites to which they are site-faithful in consecutive years. At the last wintering site, birds find themselves at the southern edge of the Sahelian zone and have no other options than facing deteriorating conditions. We tracked 36 Montagu's Harriers with GPS trackers to study their habitat use and behaviour during winter and collected data on the abundance of their main prey, grasshoppers, in Senegal. Since grasshopper abundance was positively related to vegetation greenness (measured as normalized difference vegetation index, NDVI), we used NDVI values as a proxy for prey abundance in areas where no field data were collected. Prey abundance (grasshopper counts and vegetation greenness) at wintering sites of Montagu's Harriers decreased during the wintering period. Montagu's Harriers responded to decreasing food availability by increasing their flight time during the second half of the winter. Individuals increased flight time more in areas with stronger declines in NDVI values, suggesting that lower food abundance required more intense foraging to achieve energy requirements. The apparent consequence was that Montagu's Harriers departed later in spring when their final wintering site had lower NDVI values and presumably lower food abundance and consequently arrived later at their breeding site. Our results confirmed the suggestions Moreau made 40 years ago: the late wintering period might be a bottleneck during the annual cycle with possible carry-over effects to the breeding season. Ongoing climate change with less rainfall in the Sahel region paired with increased human pressure on natural and agricultural habitats resulting in degradation and desertification is likely to make this period more demanding, which may negatively impact populations of migratory birds using the Sahel.

FIGURE 9 in A review of East and Central African species of Letheobia Cope, revived from the synonymy of Rhinotyphlops Fitzinger, with descriptions of five new species (Serpentes: Typhlopidae)

FIGURE 9. Dorsal, lateral and ventral views of head of: A. L. uluguruensis (MCZ 23081, paratype – Nyange, Tanzania, after Roux-Estève 1974: Fig. 23); B. L. somalica (MNHN 1904.603, syntype of Typhlops acutirostris Mocquard – Shoa Province, Ethiopia, after Roux-Estève 1974: Fig. 140); C. L. erythraea (NMW 16949 – Gheleb, Eritrea, D. G. Broadley illustration). The lines indicate 1 mm to scale.

FIGURE 5 in A review of East and Central African species of Letheobia Cope, revived from the synonymy of Rhinotyphlops Fitzinger, with descriptions of five new species (Serpentes: Typhlopidae)

FIGURE 5. The Letheobia rufescens complex: dorsal, lateral and ventral views of head of: A. L. largeni sp. nov. (BMNH 1974.5162, holotype – Gambela, Ethiopia, after Largen, 1978: Fig. 7); B. L. wittei (IRSNB 2511, holotype – Vandia-poshe, Democratic Republic of Congo, after Roux-Estève, 1974: Fig. 179); C. L. rufescens (MNHN 1916.262, holotype – Haut Oubangui, Central African Republic, after Roux-Estève, 1974: Fig. 167). The lines indicate 1 mm to scale.

FIGURE 6 in A review of East and Central African species of Letheobia Cope, revived from the synonymy of Rhinotyphlops Fitzinger, with descriptions of five new species (Serpentes: Typhlopidae)

FIGURE 6. The Letheobia gracilis complex: dorsal, lateral and ventral views of head of: A. L. debilis (ZFMK 33684, holotype – Bangui, Central African Republic, after Joger, 1990: Fig. 3); B. L. kibarae (IRSNB 2201, holotype – Kaswabilenga, Democratic Republic of Congo, after Witte, 1953: Fig. 35); C. L. graueri (MCZ 30034 – Rwanda, near Ujiji, Tanzania, J. Boundy illustration). The lines indicate 1 mm to scale.

FIGURE 2 in A review of East and Central African species of Letheobia Cope, revived from the synonymy of Rhinotyphlops Fitzinger, with descriptions of five new species (Serpentes: Typhlopidae)

FIGURE 2. Hypothesis of phylogenetic relationships of Typhlopoidea species groups (after Wallach, 1998b: Fig. 4).

FIGURE 8 in A review of East and Central African species of Letheobia Cope, revived from the synonymy of Rhinotyphlops Fitzinger, with descriptions of five new species (Serpentes: Typhlopidae)

FIGURE 8. The Letheobia unitaeniata complex: dorsal, lateral and ventral views of A. L. unitaeniata (MCZ 48058 – Amboni Estate, Tanzania, after Roux-Estève 1974, Fig. 180); B. L. ataeniata (CAS 151200 – Mareri, Juba River, Somalia, J. Boundy illustration); C. L. scorteccii (MCZ 74455, holotype – Afgoi, Somalia, after Roux-Estève 1974: Fig. 184). The lines indicate 1 mm to scale.

FIGURE 7 in A review of East and Central African species of Letheobia Cope, revived from the synonymy of Rhinotyphlops Fitzinger, with descriptions of five new species (Serpentes: Typhlopidae)

FIGURE 7. Dorsal, lateral and ventral views of: A. L. gracilis (ZMB 44030, holotype – Kitungulu, Zimbabwe, after Witte, 1966: Fig. 5); B. L. sudanensis (MRAC 3232, paratype – Faradje, Democratic Republic of Congo, after Roux- Estève, 1974: Fig. 171); C. L. lumbriciformis (ZMB 8045A, syntype – Zanzibar coast, after Roux-Estève, 1974: Fig. 155. The lines indicate 1 mm to scale.

FIGURE 1 in A review of East and Central African species of Letheobia Cope, revived from the synonymy of Rhinotyphlops Fitzinger, with descriptions of five new species (Serpentes: Typhlopidae)

FIGURE 1. Histograms showing number of specimens in each 1 cm size class for Letheobia species. The vertical units shown for L. wittei indicate single specimens.

FIGURE 3 in A review of East and Central African species of Letheobia Cope, revived from the synonymy of Rhinotyphlops Fitzinger, with descriptions of five new species (Serpentes: Typhlopidae)

FIGURE 3. The Letheobia obtusa complex: dorsal, lateral and ventral views of head of: A. L. obtusa (BMNH 1947.1.1.24 – Blantyre, Malawi, after Roux-Estève, 1974: Fig. 42); B. L. decorosa (MNHN 1966-1251 – Ngaoundéré, Cameroon, after Roux-Estève, 1974: Fig. 44); C. L. jubana sp. nov. (CAS 151201, holotype – Mareri, Juba River, Somalia, J. Boundy illustration). The lines indicate 1 mm to scale.

FIGURE 11 in A review of East and Central African species of Letheobia Cope, revived from the synonymy of Rhinotyphlops Fitzinger, with descriptions of five new species (Serpentes: Typhlopidae)

FIGURE 11. Distribution of the north-central African species of Letheobia and L. jubana in north-east Africa (inset, top left).

FIGURE 4 in A review of East and Central African species of Letheobia Cope, revived from the synonymy of Rhinotyphlops Fitzinger, with descriptions of five new species (Serpentes: Typhlopidae)

FIGURE 4. The Letheobia pallida complex: A. L. pallida (BMNH 68.2.9.135 – Zanzibar, after Roux-Estève, 1974: Fig. 151); B. L. swahilica sp. nov. (MCZ 40076, holotype – Ngatana, Tana River, Kenya, J. Boundy illustration); C. L. toritensis sp. nov. (NMZB 16722, paratype – Torit, Sudan, J. Boundy illustration). The lines indicate 1 mm to scale.

opennotspecifiedDec 2008View details →

FIGURES 9–12. Pseudotremia schneiderae, n in Cave millipeds of the United States. VII. New species and records of the genus Pseudotremia Cope. I. Species from West Virginia, USA (Diplopoda, Chordeumatida, Cleidogonidae)

FIGURES 9–12. Pseudotremia schneiderae, n. sp. 9. Gonopods, anterior view. 10. Gonopods, lateral view. 11. Right leg 9 of male, anterior view. 12. Right cyphopod, ventral view.

opennotspecifiedDec 2008View details →

FIGURES 5–8. Pseudotremia fongi, n in Cave millipeds of the United States. VII. New species and records of the genus Pseudotremia Cope. I. Species from West Virginia, USA (Diplopoda, Chordeumatida, Cleidogonidae)

FIGURES 5–8. Pseudotremia fongi, n. sp. 5. Gonopods, anterior view. 6. Gonopods, lateral view. 7. Right leg 9 of male, anterior view. 8. Right cyphopod, ventral view.