Integrating vital rates explains optimal worker size for resource return by bumblebee workers

AbstractPopulation persistence is strongly determined by climatic variability. Changes in the patterns of climatic events linked to global warming may alter population dynamics, but their effects may be strongly modulated by biotic interactions. Plant populations interact with each other in such a way that responses to climate of a single population may impact the dynamics of the whole community. In this study, we assess how climate variability affects persistence and coexistence of two dominant plant species in a semiarid shrub community on gypsum soils. We use 9 years of demographic data to parameterize demographic models and to simulate population dynamics under different climatic and ecological scenarios. We observe that populations of both coexisting species may respond to common climatic fluctuations both similarly and in idiosyncratic ways, depending on the yearly combination of climatic factors. Biotic interactions (both within and among species) modulate some of their vital rates, but their effects on population dynamics highly depend on climatic fluctuations. Our results indicate that increased levels of climatic variability may alter interspecific relationships. These alterations might potentially affect species coexistence, disrupting competitive hierarchies and ultimately leading to abrupt changes in community composition.

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Impact of “non-lethal” tarsal clipping on bumble bees (Bombus vosnesenskii) may depend on queen stage and worker size

Journal of Insect Conservation ◽

10.1007/s10841-021-00297-9 ◽

2021 ◽

Author(s):

John M. Mola ◽

Clara Stuligross ◽

Maureen L. Page ◽

Danielle Rutkowski ◽

Neal M. Williams

Keyword(s):

Genetic Material ◽

Population Monitoring ◽

First Year ◽

Negative Effects ◽

Worker Size ◽

Monitoring Tools ◽

Individual Survival ◽

Body Sizes ◽

Negative Effect ◽

Worker Caste

Abstract Recent bumble bee declines have prompted the development of novel population monitoring tools, including the use of putatively non-lethal tarsal clipping to obtain genetic material. However, the potential side effects of tarsal clipping have only been tested in the worker caste of a single domesticated species, prompting the need to more broadly test whether tarsal clipping negatively affects sampled individuals. To determine if tarsal clipping reduces queen survivorship and colony establishment, we collected wild queens of Bombus vosnesenskii and clipped tarsi from a single leg of half the individuals. We reared captive queens and estimated survivorship and nest establishment success. We also clipped tarsi of workers from a subset of colonies across a range of body sizes. We found no consistent negative effect of clipping on queen survival. In the first year, clipped nest-searching queens suffered heavy mortality, but there was no effect on foraging queens. The following year, we found no effect of clipping on queen survival or establishment. Clipping did not reduce overall worker survival but reduced survivorship for those in the smallest size quartile. Implications for insect conservation Our findings suggest tarsal clipping does not have consistent negative effects on individual survival. However, our results varied with queen behavioral state, year, and worker size, suggesting differences within and among species and interactions with landscape stressors warrant further study. In the interim, we recommend researchers and conservationists minimize the use of tarsal clipping for sensitive species, populations, or small workers except in cases of exceptional scientific need.

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Vital rates of two small populations of brown bears in Canada and range‐wide relationship between population size and trend

Ecology and Evolution ◽

10.1002/ece3.7301 ◽

2021 ◽

Vol 11 (7) ◽

pp. 3422-3434

Author(s):

Michelle L. McLellan ◽

Bruce N. McLellan ◽

Rahel Sollmann ◽

Heiko U. Wittmer

Keyword(s):

Population Size ◽

Small Populations ◽

Vital Rates ◽

Brown Bears

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Within- and among-population variation in vital rates and population dynamics in a variable environment

Ecological Applications ◽

10.1890/15-1808.1 ◽

2016 ◽

Vol 26 (7) ◽

pp. 2086-2102 ◽

Cited By ~ 21

Author(s):

Simone Vincenzi ◽

Marc Mangel ◽

Dusˇan Jesensˇek ◽

John C. Garza ◽

Alain J. Crivelli

Keyword(s):

Population Dynamics ◽

Population Variation ◽

Vital Rates ◽

Variable Environment

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Severity Scoring of Behavioral Responses of Sperm Whales (Physeter macrocephalus) to Novel Continuous versus Conventional Pulsed Active Sonar

Journal of Marine Science and Engineering ◽

10.3390/jmse9040444 ◽

2021 ◽

Vol 9 (4) ◽

pp. 444

Author(s):

Charlotte Curé ◽

Saana Isojunno ◽

Marije L. Siemensma ◽

Paul J. Wensveen ◽

Célia Buisson ◽

...

Keyword(s):

Behavioral Responses ◽

Physeter Macrocephalus ◽

Vital Rates ◽

Sperm Whales ◽

Experimental Conditions ◽

Active Sonar ◽

Lower Amplitude ◽

Pilot Whales ◽

New Generation ◽

Free Ranging

Controlled exposure experiments (CEEs) have demonstrated that naval pulsed active sonar (PAS) can induce costly behavioral responses in cetaceans similar to antipredator responses. New generation continuous active sonars (CAS) emit lower amplitude levels but more continuous signals. We conducted CEEs with PAS, CAS and no-sonar control on free-ranging sperm whales in Norway. Two panels blind to experimental conditions concurrently inspected acoustic-and-movement-tag data and visual observations of tagged whales and used an established severity scale (0–9) to assign scores to putative responses. Only half of the exposures elicited a response, indicating overall low responsiveness in sperm whales. Responding whales (10 of 12) showed more, and more severe responses to sonar compared to no-sonar. Moreover, the probability of response increased when whales were previously exposed to presence of predatory and/or competing killer or long-finned pilot whales. Various behavioral change types occurred over a broad range of severities (1–6) during CAS and PAS. When combining all behavioral types, the proportion of responses to CAS was significantly higher than no-sonar but not different from PAS. Responses potentially impacting vital rates i.e., with severity ≥4, were initiated at received cumulative sound exposure levels (dB re 1 μPa2 s) of 137–177 during CAS and 143–181 during PAS.

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Robustness of life histories to environmental variability in complex versus simple life cycles

Theoretical Ecology ◽

10.1007/s12080-021-00501-1 ◽

2021 ◽

Author(s):

Annie Jonsson

Keyword(s):

Growth Rate ◽

Life Histories ◽

Environmental Variability ◽

Life Cycles ◽

Relative Advantage ◽

Complex Life Cycle ◽

Life Stages ◽

Vital Rates ◽

Habitat Separation ◽

Simple Life

AbstractMost animal species have a complex life cycle (CLC) with metamorphosis. It is thus of interest to examine possible benefits of such life histories. The prevailing view is that CLC represents an adaptation for genetic decoupling of juvenile and adult traits, thereby allowing life stages to respond independently to different selective forces. Here I propose an additional potential advantage of CLCs that is, decreased variance in population growth rate due to habitat separation of life stages. Habitat separation of pre- and post-metamorphic stages means that the stages will experience different regimes of environmental variability. This is in contrast to species with simple life cycles (SLC) whose life stages often occupy one and the same habitat. The correlation in the fluctuations of the vital rates of life stages is therefore likely to be weaker in complex than in simple life cycles. By a theoretical framework using an analytical approach, I have (1) derived the relative advantage, in terms of long-run growth rate, of CLC over SLC phenotypes for a broad spectrum of life histories, and (2) explored which life histories that benefit most by a CLC, that is avoid correlation in vital rates between life stages. The direction and magnitude of gain depended on life history type and fluctuating vital rate. One implication of our study is that species with CLCs should, on average, be more robust to increased environmental variability caused by global warming than species with SLCs.

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