| 1. |
- Hagström, Charlotta, et al.
(författare)
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The effect of prescribed burning on Pulsatilla vernalis at Marma military training area in Sweden
- 2023
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Ingår i: Conservation Evidence Journal. - : Department of Zoology, University of Cambridge. - 1758-2067. ; 20, s. 13-20
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Tidskriftsartikel (refereegranskat)abstract
- Changes in habitat have led to a decline in many species which are now threatened. One of them is the spring pasque flower Pulsatilla vernalis, which grows on well-drained soils and is sensitive to competition. The species has in the past benefited from disturbances such as grazing, mowing and forest fires. Now that these do not occur as frequently, it has been suggested that prescribed burning could be used as a conservation intervention to benefit P. vernalis. In this study, we tested whether prescribed burning in 2018 benefited a population of P. vernalis at Marma military training area, outside Älvkarleby in eastern Sweden. Due to unexpected windy conditions on the day of the prescribed burning, not all the planned area was burned. This created a natural experiment that enabled us to compare burned areas with unburned areas (control) in both heathland and forested heathland habitats. The study includes data gathered before and after the experimental treatment. We found that compared to the control areas, the burned areas had a significantly higher number of P. vernalis tufts (clusters of leaf rosettes), as well as a greater number of flower stalks per tuft. Although limited due to lack of replication, this study supports the suggestion that prescribed burning benefits P. vernalis, both in open areas as well as in forests.
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| 2. |
- Hedberg, H. Roberta, et al.
(författare)
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A new player in the Panamanian fig tree – fig wasp mutualism : a study on the effect of gall midges on Ficus citrifolia
- 2024
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Ingår i: Acta Oecologica. - : Elsevier. - 1146-609X .- 1873-6238. ; 122
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Tidskriftsartikel (refereegranskat)abstract
- The mutualism between the fig tree and the pollinating fig wasps is a keystone interaction in tropical forests. However, many antagonistic interactions also occur in the system, taking advantage of the fig trees and the pollinator. One such example is an antagonistic gall midge (Cecidomyiidae) that develops inside figs. Gall midges inside figs have been documented in a few Ficus species around the world, but to our knowledge they have not previously been observed in Panama. In this study the newly observed Panamanian fig gall midge is documented, together with its parasitoid wasp. The fig gall midge was only found in Ficus citrifolia figs. We investigated the effect of fig gall midge presence on the number of seeds and the number of pollinating wasps (Pegoscapus tonduzi) in a fig and aimed to identify the species based on morphology and barcoding of the COI region. We found that the fig gall midge had no, or a negligible effect, on the reproduction of the fig tree - fig wasp mutualism. The fig gall midge most likely belongs to the genus Ficiomyia, close to Ficiomyia perarticulata. The parasitoid belongs to the genus Physothorax, close to Physothorax russelli. This study suggests that the potentially newly arrived fig gall midge currently has no major effect on the fig tree - fig wasp mutualism. However, should infestation rates increase, it is likely that the fig gall midge would affect the mutualism negatively as it has in other parts of the world. More studies on the fig gall midge species distributions in this region would be valuable and would connect these newly observed species to a larger community, adding yet another species to this complex but classic example of a mutualism.
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| 3. |
- Herre, Edward Allen, et al.
(författare)
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Evolutionary Ecology of Figs and Their Associates: Recent Progress and Outstanding Puzzles
- 2008
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Ingår i: Annual Review of Ecology, Evolution and Systematics. - : Annual Reviews. - 1543-592X .- 1545-2069. ; 39:1, s. 439-458
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Tidskriftsartikel (refereegranskat)abstract
- Over the past decade a proliferation of research has enriched and dramatically altered our understanding of the biology of figs, their pollinator wasps, and the myriad of other organisms that depend on them. Ecologically, this work underscores the crucial role that fig fruits play in sustaining and shaping tropical frugivore communities. More generally, this work addresses several key issues in evolutionary ecology, including evolution of breeding systems (shifts between monoecy and dioecy), factors that promote the stability of mutualisms, precision of adaptation, and trajectories of community assembly and coevolution in systems with multiple interacting partners. Moreover, both the pollinating and nonpollinating wasps associated with figs provide unparalleled opportunities for examining how different population structures can differentially affect sex allocation, kin selection, the evolution of parasite virulence, and many fundamental parameters of population genetics (e.g., levels of genetic variation and rates of silent and nonsilent base substitutions).
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| 4. |
- Jandér, Charlotte, et al.
(författare)
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Precision of host sanctions in the fig tree-fig wasp mutualism : consequences for uncooperative symbionts
- 2012
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 15:12, s. 1362-1369
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Tidskriftsartikel (refereegranskat)abstract
- Host sanctions that reduce the relative fitness of uncooperative symbionts provide a mechanism that can limit cheating and thus stabilise mutualisms over evolutionary timescales. Sanctions have been demonstrated empirically in several mutualisms. However, if multiple individual symbionts interact with each host, the precision with which individual cheating symbionts are targeted by host sanctions is critical to their short- and long-term effectiveness. No previous empirical study has directly addressed this issue. Here, we report the precision of host sanctions in the mutualism between fig trees and their pollinating wasps. Using field experiments and molecular parentage analyses, we show that sanctions in Ficus nymphaeifolia act at the level of entire figs (syconia), not at the level of the individual flowers within. Such fig-level sanctions allow uncooperative wasps, which do not bring pollen, to avoid sanctions in figs to which other wasps bring pollen. We discuss the relevance of sanction precision to other mutualisms.
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| 5. |
- Jandér, K. Charlotte
(författare)
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Fitness costs for fig wasps that fail to pollinate their host Ficus perforata
- 2021
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Ingår i: Symbiosis. - : Springer. - 0334-5114 .- 1878-7665. ; 84:2, s. 171-178
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Tidskriftsartikel (refereegranskat)abstract
- Mutualisms are of fundamental ecological importance, but risk breaking down if one partner stops paying the costs yet still takes the benefits of the interaction. To prevent such cheating, many mutualisms have mechanisms that lower the fitness of uncooperative symbionts, often termed host sanctions. In mutualisms where the interacting partners are species-specific, we would expect to see coevolution of the levels of host sanctions and partner cooperation across species-pairs. In the mutualism between fig trees and their species-specific pollinating fig wasps, host sanctions vary greatly in strength, and wasp cooperation levels vary accordingly. Here I show experimentally that in Panamanian Ficus perforata (section Urostigma, Americana) there are fitness costs for wasps that do not pollinate. These fitness costs are caused by a combination of abortions of unpollinated figs and reduced proportion of wasp larvae that successfully develop to adults. The relative fitness of wasps that do not pollinate compared to wasps that pollinate is 0.59, leading to the intermediate sanction strength 0.41. Next, by screening pollinators of F. perforata I found that 1.9% of wasp individuals in natural populations failed to carry pollen. Across five actively pollinated Neotropical fig species and their pollinators, fig species with stronger host sanctions had fewer uncooperative wasps, as would be expected if sanctions promote cooperation.
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| 6. |
- Jandér, K. Charlotte, et al.
(författare)
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Host sanctions and pollinator cheating in the fig tree-fig wasp mutualism
- 2010
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 277:1687, s. 1481-1488
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Tidskriftsartikel (refereegranskat)abstract
- Theory predicts that mutualisms should be vulnerable to invasion by cheaters, yet mutualistic interactions are both ancient and diverse. What prevents one partner from reaping the benefits of the interaction without paying the costs? Using field experiments and observations, we examined factors affecting mutualism stability in six fig tree-fig wasp species pairs. We experimentally compared the fitness of wasps that did or did not perform their most basic mutualistic service, pollination. We found host sanctions that reduced the fitness of non-pollinating wasps in all derived, actively pollinated fig species (where wasps expend time and energy pollinating), but not in the basal, passively pollinated fig species (where wasps do not). We further screened natural populations of pollinators for wasp individuals that did not carry pollen ('cheaters'). Pollen-free wasps occurred only in actively pollinating wasp species, and their prevalence was negatively correlated with the sanction strength of their host species. Combined with previous studies, our findings suggest that (i) mutualisms can show coevolutionary dynamics analogous to those of 'arms races' in overtly antagonistic interactions; (ii) sanctions are critical for long-term mutualism stability when providing benefits to a host is costly, and (iii) there are general principles that help maintain cooperation both within and among species.
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| 7. |
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| 8. |
- Jander, K. Charlotte
(författare)
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Indirect mutualism : ants protect fig seeds and pollen dispersers from parasites
- 2015
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Ingår i: Ecological Entomology. - : Wiley. - 0307-6946 .- 1365-2311. ; 40:5, s. 500-510
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Tidskriftsartikel (refereegranskat)abstract
- 1. Mutualisms are ubiquitous and ecologically important, but may be particularly vulnerable to exploitation by species outside of the mutualism owing to a combination of an attractive reward and potentially limited defence options. For some mutualisms, ants can offer dynamic and relatively selective protection against herbivores and parasites. 2. The mutualism between fig trees and their pollinating wasps, a keystone mutualism in tropical forests, is particularly well suited for ant protection because pollinators are protected inside hollow inflorescences but parasites are exposed on the outside. 3. In the present study, it was shown that the presence of ants provides a fitness benefit for both the pollinators and the hosting fig tree. The presence of ants (i) reduced abortions of developing figs, (ii) reduced herbivory of figs, and (iii) reduced parasitic wasp loads, resulting in more pollinators and more seeds in ant-protected figs. Even when taking costs such as ant predation on emerging pollinators into account, the total fitness increase of hosting ants was threefold for the tree and fivefold for the pollinators. 4. It was further shown that the seemingly most vulnerable parasitic wasps, of the genus Idarnes, have a specific behaviour that allows them to evade ant attack while continuing to oviposit. 5. Ants were present on 79% of surveyed Panamanian fig trees. Together with previous studies from the Old World, the results found here imply that ants are both powerful and common protectors of the fig mutualism worldwide.
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| 9. |
- Jandér, K. Charlotte, et al.
(författare)
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Third and fourth degree perineal tears : Risk factors in a referral hospital
- 2001
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Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - : John Wiley & Sons. - 0001-6349 .- 1600-0412. ; 80:3, s. 229-234
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Tidskriftsartikel (refereegranskat)abstract
- Background: Tears of the anal sphincter are a feared complication of vaginal delivery, as many as 50% of these patients experience incontinence as an after-effect. Identifying significant predictor factors leading to third or fourth degree perineal tears during vaginal delivery was the objective of this study. Methods: During a two-year period (1995-1996), a third or fourth degree perineal rupture occurred in 214 women (3.7%) after vaginal delivery. Data from these deliveries were collected and compared to data from deliveries without anal sphincter tears in order to identify risk factors. A stepwise logistic regression model was used for the analysis. Results: Independent risk factors of significance were vaginal nulliparity, a squatting position on a delivery chair, maternal age exceeding 35 years, baby's birth weight over 4000 g, vacuum extraction (both outlet and mid release), median episiotomy, oxytocin augmentation and birthing between 3 a.m. and 6 a.m. Conclusions: This study identified several factors associated with anal sphincter tears. Median episiotomy should be avoided. Delivery, while squatting on a low chair, should be used with caution. A woman with one or more risk factors requires caution by birth attendants during delivery. Gynecologists should consider the option of cesarean section instead of vacuum extraction, especially when mid release is needed in the presence of macrosomia. A continuous audit regarding instrumental delivery technique is necessary.
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| 10. |
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