scholarly journals Resource exchange and partner recognition mediate mutualistic interactions between prey and their would-be predators

2021 ◽  
Vol 17 (8) ◽  
pp. 20210316
Author(s):  
Luis F. Camacho ◽  
Leticia Avilés
Keyword(s):  
Prey Type ◽  
Alternative Prey ◽  
Resource Exchange ◽  
Similar Extent ◽  
Proximate Mechanisms ◽  
Recognition Response ◽  
Potential Sources ◽  
Mutualistic Interactions

Animals may develop mutualistic associations with other species, whereby prey offer resources or services in exchange for protection from predators. Alternatively, prey may offer resources or services directly to their would-be predators in exchange for their lives. The latter may be the case of hemipterans that engage in mutualistic interactions with ants by offering a honeydew reward. We test the extent to which a honeydew offering versus partner recognition may play a role as proximate mechanisms deterring ants from predating upon their hemipteran partners. We showed that, when presented with a choice between a hemipteran partner and an alternative prey type, mutualist ants were less likely to attack and more likely to remain probing their hemipteran partners. This occurred even in the absence of an immediate sugary reward, suggesting either an evolved or learned partner recognition response. To a similar extent, however, ants were also less likely to attack the alternative prey type when laced with honey as a proxy for a honeydew reward. This was the case even after the honey had been depleted, suggesting an ability of ants to recognize new potential sources of sugars. Either possibility suggests a degree of innate or learned partner recognition.

scholarly journals Diversity within mutualist guilds promotes coexistence and reduces the risk of invasion from an alien mutualist

2020 ◽  
Vol 287 (1923) ◽  
pp. 20192312 ◽  
Author(s):  
Maria M. Martignoni ◽  
Miranda M. Hart ◽  
Rebecca C. Tyson ◽  
Jimmy Garnier
Keyword(s):  
Mathematical Model ◽  
Conservation Biology ◽  
Competitive Exclusion ◽  
Species Coexistence ◽  
Propagule Pressure ◽  
Invasion Success ◽  
Competitive Interactions ◽  
Resource Exchange ◽  
Mutualistic Interactions

Biodiversity is an important component of healthy ecosystems, and thus understanding the mechanisms behind species coexistence is critical in ecology and conservation biology. In particular, few studies have focused on the dynamics resulting from the co-occurrence of mutualistic and competitive interactions within a group of species. Here we build a mathematical model to study the dynamics of a guild of competitors who are also engaged in mutualistic interactions with a common partner. We show that coexistence as well as competitive exclusion can occur depending on the competition strength and on strength of the mutualistic interactions, and we formulate concrete criteria for predicting invasion success of an alien mutualist based on propagule pressure, alien traits (such as its resource exchange ability) and composition of the recipient community. We find that intra guild diversity promotes the coexistence of species that would otherwise competitively exclude each other, and makes a guild less vulnerable to invasion. Our results can serve as a useful framework to predict the consequences of species manipulation in mutualistic communities.

Prey preferences of Phaeacius malayensis, a spartaeine jumping spider (Araneae: Salticidae) from Singapore

2000 ◽  
Vol 78 (12) ◽  
pp. 2218-2226 ◽  
Author(s):  
Daiqin Li
Keyword(s):  
Optimal Foraging ◽  
Prey Type ◽  
Optimal Foraging Theory ◽  
Simultaneous Presentation ◽  
Adaptive Significance ◽  
Alternative Prey ◽  
Jumping Spider ◽  
Jumping Spiders ◽  
Prey Preferences ◽  
Different Types

Phaeacius malayensis (Salticidae: Spartaeinae) is an atypical jumping spider that routinely includes other jumping spiders in its diet. This paper presents the first detailed study of P. malayensis' prey preferences. Three basic types of tests of prey preference were used: different types of prey were provided on alternate days (alternate-day tests), two types of prey were provided simultaneously (simultaneous-presentation tests), and an alternative prey type was provided while the predator was already feeding (alternative-prey tests). In alternate-day and simultaneous-presentation testing, but not in alternative-prey testing, (i) P. malayensis preferred spiders (salticids and hunting spiders) to insects; (ii) P. malayensis preferred salticids to hunting spiders; (iii) these preferences were not exhibited in some paired choices when the background was nonmatching, indicating that visual concealment is important with respect to some, but not all, prey; (iv) P. malayensis' prey preferences were not affected by a prior 14-day period without food; (v) after 21 days of fasting, P. malayensis took different types of prey indiscriminately. The adaptive significance of preferences for particular types of prey is discussed in the context of optimal-foraging theory.

Diet composition, prey choice, and breeding success of Long-eared Owls: effects of multiannual fluctuations in food abundance

1992 ◽  
Vol 70 (12) ◽  
pp. 2373-2381 ◽  
Author(s):  
Erkki Korpimäki
Keyword(s):  
Diet Composition ◽  
Common Vole ◽  
Prey Type ◽  
Clethrionomys Glareolus ◽  
Alternative Prey ◽  
Optimal Diet ◽  
Bank Voles ◽  
Vole Cycle ◽  
The Common ◽  
Common Voles

Common voles (Microtus epiroticus) were the main prey of Long-eared Owls (Asio otus) breeding in western Finland during 1977 – 1989. They constituted, on average, 58% (range < 15 to > 75%) of the number of prey. Field voles (Microtus agrestis), common shrews (Sorex araneus), bank voles (Clethrionomys glareolus), and water voles (Arvicola terrestris) were the most frequent alternative prey. The owls showed strong preference for common voles over the alternative prey species and this preference increased with vole density. If the common vole is the most profitable prey of Long-eared Owls, the between-years variation in the diet was consistent with the three predictions of the conventional model of the optimal diet theory. (1) Predators should feed on the most valuable prey type when prey are abundant. There was a positive correlation between the abundance of common voles and their proportions in the food. (2) No relationships for alternative prey types agreed with the prediction that the inclusion of a prey type in the diet depends only on the abundance of the preferred prey. (3) As predicted by the optimal diet theory, the diet width expanded when the density of common voles decreased and shrank when vole density increased. Annual breeding density (range 0.0–0.4 nests/km2), mean clutch size (3.0 – 6.3), and mean brood size (0.0 – 3.5) were positively related to the spring abundance of common and field voles. Accordingly, it is adaptive for Long-eared Owls to breed in a good area for voles. Because vole abundances in Fennoscandia fluctuate markedly between years and asynchronously between areas, Long-eared Owls should stay in the same area in the increase phase of the vole cycle, but move away when voles decline.

Control in Flexible Working Arrangements

2015 ◽  
Vol 14 (2) ◽  
pp. 61-69 ◽  
Author(s):  
Cornelia Gerdenitsch ◽  
Bettina Kubicek ◽  
Christian Korunka
Keyword(s):  
Self Determination Theory ◽  
Digital Natives ◽  
Self Determination ◽  
Structured Interviews ◽  
Similar Extent ◽  
Decision Latitude ◽  
Media Technologies ◽  
Exploratory Approach ◽  
Flexible Working ◽  
Temporal And Spatial

Supported by media technologies, today’s employees can increasingly decide when and where to work. The present study examines positive and negative aspects of this temporal and spatial flexibility, and the perceptions of control in these situations based on propositions of self-determination theory. Using an exploratory approach we conducted semi-structured interviews with 45 working digital natives. Participants described positive and negative situations separately for temporal and spatial flexibility, and rated the extent to which they felt autonomous and externally controlled. Situations appraised positively were best described by decision latitude, while negatively evaluated ones were best described by work–nonwork conflict. Positive situations were perceived as autonomous rather than externally controlled; negative situations were rated as autonomously and externally controlled to a similar extent.

Australasian Huperzia as potential sources of Huperzine A and B

Planta Medica ◽  
2009 ◽  
Vol 75 (09) ◽  
Author(s):  
WH Lim ◽  
JQG Goodger ◽  
AR Field ◽  
JAM Holtum ◽  
IE Woodrow
Keyword(s):  
Huperzine A ◽  
Potential Sources

PHENOLIC METABOLITES OF DL-NORGESTREL: A METHOD FOR THE REMOVAL OF 1-HYDROXYLATED METABOLITES, POTENTIAL SOURCES OF PHENOLIC ARTIFACTS

1974 ◽  
Vol 76 (4) ◽  
pp. 789-800 ◽  
Author(s):  
Samuel F. Sisenwine ◽  
Ann L. Liu ◽  
Hazel B. Kimmel ◽  
Hans W. Ruelius
Keyword(s):  
Urinary Metabolites ◽  
Ion Exchange Resin ◽  
Gas Chromatography Mass Spectrometry ◽  
Phenolic Metabolites ◽  
Hydroxylated Metabolites ◽  
Analytical Work ◽  
Potential Sources ◽  
Alkaline Conditions ◽  
Artifact Formation ◽  
Work Up

ABSTRACT The identification of 1β-hydroxynorgestrel among the urinary metabolites of dl-norgestrel and the facile transformation of this compound under mild alkaline conditions to a potentially oestrogenic phenol provide an experimental basis for the conclusion advanced by others that the oestrogens present in the urine of subjects treated with synthetic progestens are artifacts formed during analytical work-up. A method has been devised which eliminates 1-hydroxylated metabolites as potential sources of phenolic artifacts. This method is based on the reduction by NaBH4 of the 1-hydroxy-4-en-3-one grouping in the A ring thereby excluding the possibility of aromatization during later fractionation on a basic ion exchange resin that separates neutral from phenolic metabolites. In the urines of women treated with 14C-dl-nogestrel, only 0.17–0.27% of the dose is found to have phenolic properties when this method is used. Two of the phenolic metabolites, 18-homoethynyloestradiol and 16β-hydroxy-18-homoethynyloestradiol, are present in amounts smaller than 0.01 % of the dose. Without the reduction steps the percentages are noticeably higher, indicating artifact formation under alkaline conditions. Similar results were obtained with urines from African Green Monkeys (Cercopithecus Aethiops) that had been dosed with 14C-dl-norgestrel. Radiolabelled 18-homoethynyloestradiol and 16β-hydroxy-18-homoethynyloestradiol were isolated from monkey urine and their identity confirmed by gas chromatography-mass spectrometry.

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