An extended food web from Greenland : adding birds, spiders and plants to a parasitoid-lepidopteran web

Quantitative food webs have been used since the 1990s to describe the ecology of ecosystems. Such webs describe not only 'who eats whom' but also how many individuals get eaten, giving a detailed picture of the connections in an ecosystem. This detail allows far-reaching ecological conclusions to be drawn, for all manner of questions ranging from the influence of abiotic and biotic factors on population dynamics to the effect of latitude on ecosystem structure. Currently the webs' greatest limitations are their incompleteness and lack of geographic coverage: most published webs focus on a tiny fragment of the total food web, and there are few webs from higher latitudes. In this thesis I address these limitations, by extending a parasitoid-lepidopteran web which is being collected in the High Arctic. I add data on bird and spider predation of the web's Lepidoptera, and on the lepidopterans' herbivory of their food plants. Specifically, I ask what the relative strengths of predation and parasitism are in this community, and what effect herbivory has on the plants' seed production. I measured predation rates using both live caterpillars and modelling clay dummies as bait. The former, caterpillars of Sympistis nigrita tethered to threads, gave an estimate of both spider and bird predation. The latter showed bird predation only, but gave a larger sample size than tethered caterpillars. For the herbivory rates, I measured the seed production of avens flowers (Dryas octopetala x integrifolia, one of the main lepidopteran food plants) when damaged by feeding caterpillars. I found that predation is an important cause of mortality for S. nigrita, comparable to the high rates of parasitism already observed. During the larval period, some 38% of S. nigrita caterpillars are killed by spiders, 8% by parasitoids and 8% by birds. The caterpillars ate highly variable amounts of avens flowers, with 14.4% of flowers damaged by feeding in a set of 743 flowers, and 8.3% in another set of 672 flowers. The damaged flowers produced fewer and smaller seeds than did undamaged ones, causing overall avens seed production to drop by 7%. Overall, my findings show spider predation to be a relevant addition to the current parasitoid-lepidopteran food web. Bird predation, however, is relatively light – both when compared to spider predation and also to earlier predation rates reported from warmer latitudes. It is nevertheless comparable to the (naively twice as strong) parasitism since almost half the parasites die when their host is predated. When comparing food webs in order to address large scale ecological questions, such as the effect of latitude on food web structure, broader webs may be required instead of the mere parasitoid-host webs produced to date.Määrällisiä ravintoverkkoja on käytetty 1990-luvulta lähtien kuvaamaan ekosysteemien ekologiaa. Niistä selviää sekä kuka syö ketäkin että kuinka moni yksilö tulee syödyksi – antaen tarkan kuvan lajien välisistä vuorovaikutuksista. Tällainen yksityiskohtainen ekosysteemin kuvaus mahdollistaa lukuisten ekologisten kysymysten käsittelemisen, aina abioottisten ja bioottisten tekijöiden vaikutuksesta populaatioihin siihen, miten eliöyhteisöjen rakenne vaihtelee leveyspiirin mukaan. Nykyisellään ravintoverkkojen suurimpana heikkoutena on kattavuuden puute: useimmat julkaistut verkot sisältävät vain murto-osan alueen lajeista, eikä verkkoja juurikaan ole kuvattu kylmiltä leveyspiireiltä. Työssäni täydennän verkkoja kattavammiksi laajentamalla loisten ja perhosentoukkien verkkoa, jota kerätään parhaillaan Grönlannissa: lisään verkkoon perhosentoukkien saalistajat (linnut ja hämähäkit) sekä toukkien ravintokasvin. Selvitin saalistuksen määrän levittämällä maastoon syötteinä sekä eläviä perhosentoukkia että muovailuvahasta tehtyjä keinotoukkia. Elävien toukkien – eli lankaan kiinnitettyjen Sympistis nigrita -toukkien – avulla selvitin lintujen ja hämähäkkien saalistamien toukkien määrän. Keinotoukat mittasivat ainoastaan lintujen saalistusta, mutta suuremmalla otoksella. Kasvinsyönnin laajuutta arvioin toukkien yleisimmästä ravintokasvista lapinvuokosta (Dryas octopetala x integrifolia). Mittasin kuinka moni kukista joutui toukkien syömäksi ja miten tämä vaikutti siementuottoon. Saalistus osoittautui merkittäväksi S. nigrita -toukkien kuolinsyyksi ja oli mitattua loisintaa voimakkaampaa. Kaiken kaikkiaan 38% toukista joutuu hämähäkin, 8% loisen ja 8% linnun syömäksi. Toukat söivät lapinvuokkoa vaihtelevissa määrin: 743 kukan otoksesta toukat olivat vahingoittaneet 14.4%, ja 672 kukan otoksesta 8.3% oli vahingoittunut. Vahingoittuneet kukat tuottivat vähemmän ja pienempiä siemeniä, minkä seurauksena lapinvuokon siementuotto väheni 7%. Tulosteni perusteella hämähäkit ovat Grönlannissa merkittäviä perhosentoukkien saalistajia ja ne kuuluu lisätä nykyiseen loisten ja perhosentoukkien verkkoon. Linnut sen sijaan saalistavat verraten vähän toukkia – sekä hämähäkkeihin verrattuna että myös siihen verrattuna, mitä lintujen on raportoitu saalistavan eteläisemmillä leveyspiireillä. Lintujen suorittama saalistus on kuitenkin verrattavissa loisintaan (15%), koska monet loiset kuolevat isäntänsä mukana saalistukseen jolloin lopullinen loisintaosuus puolittuu. Tulevaisuudessa saatetaan tarvita nykyisiä lois-isäntä -verkkoja laajempia ravintoverkkoja, jos ekologisia kysymyksiä halutaan ratkoa vertaamalla eri alueiden ravintoverkkoja. Näin voitaisiin esimerkiksi selvittää leveyspiirin vaikutusta eliöyhteisön rakenteeseen

On the parasitoid wasps of the African tropical forest – and how their species richness compares to Amazonia

Our planet is inhabited by an astounding diversity of species, most of which have not yet been discovered. This species richness is at its highest in the tropics and particularly in tropical insects. The tropical Darwin wasps (Hymenoptera: Ichneumonidae), which represent one of the largest animal families on Earth, are especially poorly known. So much so, that doubts persist as to their being species rich in the tropics. In this PhD, I collected Darwin wasps in tropical forest in Uganda, using large numbers of Malaise traps for a year. I then examined the species richness of one of the subfamilies (Rhyssinae), and also investigated the phenology and habitat use of the species. I compared the species richness of my Ugandan site with that of Amazonia, which had been sampled using the same methods. A year of Malaise trapping discovered six rhyssine species in Uganda. Two of these species were new to science. These results, together with the results of previous sampling at the site, clearly demonstrated that there is a diverse Darwin wasp fauna still awaiting discovery in Africa. Ugandan rhyssines were caught in largest numbers in dry weather, near decaying wood in primary forest. The results suggested they prey on wood-boring larvae, and also gave an indication of their adult lifespan. This kind of data is rarely obtained in the tropics, and I suggest applying the same methods to the results of other sampling programs. Comparing the rhyssines of two tropical forest sites on different continents suggested that the Amazonian site I compared to may have even more species than my African site. However, Amazonia did not stand out as anomalously diverse. I suggest collecting Darwin wasps from further sites using the same methods. This would answer the question of whether or not Darwin wasps are species rich throughout the tropics, with Amazonia being among the more diverse areas. Using large numbers of Malaise traps for a year gave a wealth of information on what species were present at a tropical site, how they lead their lives, and how they compare to their counterparts on another continent. Current work has only scratched the surface of the astounding diversity of tropical Darwin wasps.Planeettaamme asuttavat miljoonat eliölajit, joista useimpia ei vielä ole löydetty. Tämä ällistyttävä lajirunsaus on korkeimmillaan tropiikissa, ja trooppiset hyönteiset muodostavat siitä suuren osan. Maailman kenties lajirikkain eläinheimo, ahmaspistiäiset (Hymenoptera: Ichneumonidae), tunnetaan erityisen huonosti tropiikissa. On jopa epäilty sen olevan poikkeuksellisen vähälajinen tropiikissa. Väitöskirjaani varten keräsin ahmaspistiäisiä vuoden ajan lukuisilla Malaisepyydyksillä Ugandan trooppisessa metsässä. Tarkastelin erään alaheimon (porapistiäiset, Rhyssinae) lajirunsautta, ja selvitin miten lajit jakautuvat eri metsätyyppeihin sekä milloin ne lentävät. Lisäksi vertasin lajirunsautta Amazonin sademetsään, jossa oli kerätty ahmaspistiäisiä samalla menetelmällä. Pyydykset saivat vuoden aikana saaliiksi kuusi porapistiäislajia. Näistä kaksi oli tieteelle uusia. Nämä tulokset (ja erään aiemman keräyksen tulokset) osoittavat että Afrikassa elää runsas ja suurelta osin tuntematon loispistiäislajisto. Porapistiäisiä saatiin Ugandassa eniten sateettomalla säällä, lahopuun lähellä koskemattomassa metsässä. Tämä viittaa siihen, että ne loisivat lahopuussa eläviä toukkia. Saimme myös viitteitä siitä, kuinka pitkään ne elävät aikuisena. Tropiikista saadaan harvoin tällaista tietoa, ja suosittelenkin menetelmieni käyttämistä myös muiden trooppisten pyydystysten yhteydessä. Verratessani kahta trooppista aluetta jotka sijaitsevat eri mantereilla sain viitteitä siitä, että vertailukohtana toimiva Amazonin sademetsän alue olisi afrikkalaista tutkimusaluettanikin lajirunsaampi. Kummatkin alueet vaikuttivat kuitenkin kuuluvan samaan lajirunsauden jatkumoon. Suosittelen vastaavaa pyydystystä useammalla tutkimusalueella. Näin selviäisi, ovatko ahmaspistiäiset lajirikkaita koko tropiikissa, ja onko Amazonin sademetsä lajirikkaammasta päästä. Keruumenetelmämme, jossa lukuisia Malaisepyydyksiä käytetään vuoden ajan, antoi runsaan aineiston. Se tuotti tietoa erään trooppisen metsän lajistosta, lajien elintavoista ja siitä miten ne vertautuvat toisen mantereen vastaaviin lajeihin. Olemme vasta pääsemässä alkuun tropiikin ällistyttävän monimuotoisten ahmaspistiäisten kartoittamisessa

Uganda Malaise trapping 2014–2015 Rhyssinae ecology data

This dataset contains the data and analyses of our paper on the ecology of Ugandan Rhyssinae. We collected rhyssines by Malaise trapping in tropical forest in Kibale National Park 2014–2015. The dataset contains background data such as weather and vegetation around the traps, data on the 447 rhyssines caught, the figures in the paper, and the script used to analyse the data. The script (2 Rhyssinae ecology.R) will usually be of the greatest interest. It contains the R code used to explore and analyse the data, and to create the figures in the paper

Deducing how tropical rhyssines (Hymenoptera, Ichneumonidae) mate from body measurements

The biology of many Darwin wasp (Hymenoptera: Ichneumonidae) species is poorly known. Existing museum specimens can potentially be used to get information on e.g. how species live, what they eat, and what their life cycle is. One example of this is a 1991 study by Eggleton in which he measured some rhyssine (Ichneumonidae: Rhyssinae) species, and used the results to deduce how the species likely mate. We extend this work by measuring five tropical species. We found no evidence that the males of our species scramble for females before the females emerge, which matches what was hypothesised by Eggleton. Further measurements of more species would provide information on how other species mate, and field observations of mating rhyssines would help confirm that Eggleton's method for deducing rhyssine mating strategies gives true results

Assessing the Species Richness of Afrotropical Ichneumonid Wasps with Randomly Placed Traps Provides Ecologically Informative Data

The tropical ichneumonid wasps are poorly sampled, particularly in the Old World, despite their ecological importance and high species richness. Existing inventories also tend to have had a taxonomic focus, with trap placement reflecting the need for maximal sample size rather than rigorous ecological comparisons. Here, we report the results of an intensive sampling effort at Kibale National Park, Uganda, carried out with randomised trap locations. We sampled ichneumonid faunas for a year (2011–2012) with Malaise traps, in eight successional sites ranging from clear-cut exotic plantations to primary rainforest. The traps were situated in 10 random locations at each site and were moved between locations once a week. The total sampling effort encompassed 231 trap months (using traps smaller than the standard size), one of the largest we know of from a single Afrotropical location.We sorted the collected ichneumonids into subfamilies and investigated whether their community composition differed between the sites. Ichneumonid faunas differed between forest and former plantation sites, with both the overall difference and that of four subfamilies significant. Our sample size was unexpectedly small (1212 individuals), but we estimate that the model-based analyses we used could still have given a significant result with a smaller (954 individuals) sample. Overall, randomly placed Malaise traps detected ecological patterns in Afrotropical ichneumonid distributions. Our data also showed that there is a rich and at least partly undescribed ichneumonid fauna still awaiting discovery in the Afrotropical rainforests. Future inventories of this fauna may, however, have to compromise on objective random trap placement in order to get a large sample size.</p

Extensive sampling and thorough taxonomic assessment of Afrotropical Rhyssinae (Hymenoptera, Ichneumonidae) reveals two new species and demonstrates the limitations of previous sampling efforts

Tropical forest invertebrates, such as the parasitoid wasp family Ichneumonidae, are poorly known. This work reports some of the first results of an extensive survey implemented in Kibale National Park, Uganda. A total of 456 individuals was caught of the subfamily Rhyssinae Morley, 1913, which in the Afrotropical region was previously known from only 30 specimens. Here, the six species found at the site are described and the Afrotropical Rhyssinae are reviewed. Two new species, Epirhyssa johanna Hopkins, sp. nov. and E. quagga sp. nov., are described and a key, diagnostic characters, and descriptions for all 13 known Afrotropical species are provided, including the first description of the male of Epirhyssa overlaeti Seyrig, 1937. Epirhyssa gavinbroadi Rousse & van Noort, 2014, syn. nov. is proposed to be a synonym of E. uelensis Benoit, 1951. Extensive sampling with Malaise traps gave an unprecedented sample size, and the method is recommended for other poorly known tropical areas.</p

New national and regional biological records for Finland 10. Contributions to Bryophyta and Marchantiophyta 9

Six species of mosses (Bryophyta: Brachythecium udum, Lewinskya fastigiata, L. elegans, Polytrichastrum altaicum, P. septentrionale, Tortella densa) and two of liverworts (Marchantiophyta: Scapania parvifolia and Tritomaria excecta) are presented as new for Finland. One species, Brachythecium laetum, is removed from the Finnish checklist. New records in biogeographical provinces for 51 species of mosses and 32 species of liverworts are listed. Finally, two occurrences in biogeographical provinces are removed due to misidentifications

Higher predation risk for insect prey at low latitudes and elevations

Biotic interactions underlie ecosystem structure and function, but predicting interaction outcomes is difficult. We tested the hypothesis that biotic interaction strength increases toward the equator, using a global experiment with model caterpillars to measure predation risk. Across an 11,660-kilometer latitudinal gradient spanning six continents, we found increasing predation toward the equator, with a parallel pattern of increasing predation toward lower elevations. Patterns across both latitude and elevation were driven by arthropod predators, with no systematic trend in attack rates by birds or mammals. These matching gradients at global and regional scales suggest consistent drivers of biotic interaction strength, a finding that needs to be integrated into general theories of herbivory, community organization, and life-history evolution

New national and regional biological records for Finland 10. Contributions to Bryophyta and Marchantiophyta 9

Six species of mosses (Bryophyta: Brachythecium udum, Lewinskya fastigiata, L. elegans, Polytrichastrumaltaicum, P. septentrionale, Tortella densa) and two of liverworts (Marchantiophyta:Scapania parvifolia and Tritomaria excecta) are presented as new for Finland. One species,Brachythecium laetum, is removed from the Finnish checklist. New records in biogeographicalprovinces for 51 species of mosses and 32 species of liverworts are listed. Finally, two occurrencesin biogeographical provinces are removed due to misidentifications.</p

The impact of COVID-19 critical illness on new disability, functional outcomes and return to work at 6 months: a prospective cohort study

BackgroundThere are few reports of new functional impairment following critical illness from COVID-19. We aimed to describe the incidence of death or new disability, functional impairment and changes in health-related quality of life of patients after COVID-19 critical illness at 6 months.MethodsIn a nationally representative, multicenter, prospective cohort study of COVID-19 critical illness, we determined the prevalence of death or new disability at 6 months, the primary outcome. We measured mortality, new disability and return to work with changes in the World Health Organization Disability Assessment Schedule 2.0 12L (WHODAS) and health status with the EQ5D-5LTM.ResultsOf 274 eligible patients, 212 were enrolled from 30 hospitals. The median age was 61 (51–70) years, and 124 (58.5%) patients were male. At 6 months, 43/160 (26.9%) patients died and 42/108 (38.9%) responding survivors reported new disability. Compared to pre-illness, the WHODAS percentage score worsened (mean difference (MD), 10.40% [95% CI 7.06–13.77]; p TM utility score (MD, − 0.19 [− 0.28 to − 0.10]; p ConclusionsAt six months after COVID-19 critical illness, death and new disability was substantial. Over a third of survivors had new disability, which was widespread across all areas of functioning