Bachelor thesis in Biology The Hymenopteran subfamily Adeliinae (Braconidae) A morphological and ecological study of specimens collected in Sweden Author: Mårten Eriksson Supervisor: Dave Karlsson Supervisor: Per-Eric Betzholtz Examiner: Geoffrey Lemdahl Semester: VT13 Subject: Biology Level: Bachelor 1 Nr: 2013:Bi4 Abstract Insects are the most numerous and species rich group of animals on Earth. One of the four mega diverse orders within the class Insecta is Hymenoptera which include ants, bees and parasitic wasps. One of the many Hymenopteran subfamilies is Adeliinae, a group of tiny wasps that parasitize leaf mining Lepidoptera larvae. Only one described species of Adeliinae is hitherto known to occur in Sweden. However, this known species exhibits a wide range of polymorphism. In fact, the hypotheses if Adeliinae constitute a subfamily with just a few, but very variable species or if it is composed by a rich number of very similar species have never been tested before. The results in this study confirm the variation, but cannot state which of the hypotheses that is the most correct. Furthermore, the processed information from the traps in which the wasps were caught show that the Adeliinae are spread throughout Sweden and appear in a wide variety of habitats. Sammanfattning Insekter är den mest artrika och talrika djurgruppen på jorden. En av de fyra enormt artrika insektsordningarna inom klassen Insecta är Hymenoptera, eller steklar, som bland annat består av myror, bin och parasitsteklar. En av de många underfamiljerna bland steklarna är Adeliinae (dvärgmalsteklar), en grupp med små steklar som lägger ägg inuti larver av minerare. Det finns hittills endast en känd beskriven art i Sverige av dvärgmalsteklar. Den sedan tidigare kända arten uppvisar dock en stor variation i utseende. Faktum är att det aldrig tidigare har testats om denna underfamilj endast består av några få men mycket varierande arter eller många arter med lite skillnad. Resultatet från denna studie bekräftar den stora variationen men kan inte avgöra vilken av hypoteserna som är korrekt. Dessutom har den bearbetade informationen från de fällor där steklarna har fångats visat att underfamiljen Adeliinae är spridd över hela Sverige och förekommer i ett stort antal olika habitat. Key words Adeliinae, Braconidae, Hymenoptera, Parasitoid, Leaf miners, Morphology, Polymorphism, Characters, Distribution, Ecology Acknowledgments I would like to thank my supervisor Dave Karlsson at Station Linné for helping me through this project with ideas and a great enthusiasm, Pelle Magnusson, also at Station Linné for his expertise in Hymenoptera as well as all the members of the Swedish Malaise Trap Project for giving me a great time at their lab. For the supply of reference material and determination I would like to thank Hege Vårdal at the Natural History Museum in Stockholm, Christer Hansson at the University of Lund, Cees van Achterberg at Naturalis in Leiden, Netherlands, James O’Connor and Nigel Monaghan both at the Natural History Museum in Dublin, Ireland. I also got a lot of help with the character trees and information concerning the wasps from Seraina Klopfstein, Mattias Forshage and Julia Stigenberg, all at the Natural History Museum in Stockholm. Finally my thanks go out to my family and friends who has supported me through this project. i Table of contents 1 Introduction ............................................................................................................................. 1 1.1 The order Hymenoptera ................................................................................................... 1 1.1.1 Morphology of the Hymenopteran suborder Apocrita .............................................. 2 1.2 The family Braconidae ..................................................................................................... 5 1.3 The subfamily Adeliinae .................................................................................................. 5 1.3.1 Placement of Adeliinae within Braconidae ............................................................... 6 1.3.2 The biology of Adeliinae ........................................................................................... 7 1.3.3 The material for this thesis work ............................................................................... 7 1.3.4 Description of the species relevant for this project ................................................... 8 1.4 Nepticulidae ..................................................................................................................... 8 2 Method .................................................................................................................................... 9 2.1 Introduction to hymenoptera and an overview of the material ........................................ 9 2.2 Preparation of material and mounting of insects .............................................................. 9 2.2.1 Determination of sex ................................................................................................. 9 2.3 Examination of material and creation of a matrix .......................................................... 10 2.3.1 Creation of trees using the character matrix ............................................................ 10 2.4 Mounting and photographing of wings and wasps ......................................................... 11 2.5 Examining the ecology of Adeliinae .............................................................................. 11 2.5.1 Calculation of flight time ........................................................................................ 11 2.5.2 Creating maps of distribution in GIS ...................................................................... 12 3 Results ................................................................................................................................... 13 3.1 Results concerning morphology ..................................................................................... 13 3.1.1 Variation in wing venation ...................................................................................... 18 3.2 Distribution, habitat type and flight time ....................................................................... 19 4 Discussion ............................................................................................................................. 21 4.1 Possible sources of error ................................................................................................ 24 4.2 Future aspects and studies .............................................................................................. 25 Conclusion ................................................................................................................................ 25 References ................................................................................................................................ 26 Appendix 1 .................................................................................................................................. I Appendix 2 ................................................................................................................................ V ii 1 Introduction The aim of this study was to investigate the morphological variation, biology and occurrence in Sweden of the Hymenopteran subfamily Adeliinae (Braconidae). Adeliine wasps are seldom caught and are therefore rarely found in collections. A unique opportunity to study the group was given by the Swedish Malaise Trap Project (SMTP) in which 140 undetermined specimens are hitherto found. This study has obtained new knowledge concerning a poorly studied but truly fascinating group of tiny and beautiful wasps. 1.1 The order Hymenoptera One of the most species rich orders of insects is Hymenoptera with approximately 115 000 described species (Grissell 1999) placing them only behind Coleopterans (beetles) and Lepidopterans (butterflies). However, there are estimates that there could be as many as 1 000 000 species or more worldwide which means that more than 80 % of the species are yet undescribed and that Hymenopterans would make up about 10 % of the total number of species on Earth (Sharkey 2007). Furthermore, they come in huge numbers, a classical example being the estimate that there are over one million ants per every human being on this planet. Their great diversity and numbers means that Hymenopterans have a profound effect on the world’s ecosystems and ecology. Honey bees (genus Apis) pollinate important agricultural plants providing crops as well as producing honey to an estimated value of 14.6 billion U.S. dollars (Morse & Calderone 2000). Parasitoid Hymenoptera, since they have a wide variety of other insects as hosts, can be used as indicators of changes in the environment. Finally, the parasitoids can also be used as biological control agents against other insects that threaten biodiversity or crops (Sharkey 2007). The order Hymenoptera is divided into two suborders: Symphyta and Apocrita. Symphyta is commonly known as sawflies and contain both herbivores laying eggs in vegetation which the larvae later consume and parasitoids. Apocritan adults have a characteristic wasp waist and the group is further divided into Aculeata (stinging wasps) and Terebrantes (also known as Parasitica). Aculeata contains many of the most well known Hymenopterans such as ants, bees and yellow-jackets (Sharkey 2007). Terebrantes, originally known