Ao. Univ.-Prof. Mag. Dr. Harald W. Krenn
Integrative Zoology
UBB, Djerassiplatz 1
1030 Vienna, Austria

room: 4.045
phone: +43 1 4277 76368
mobile: +43 664 60277 76368


Terrestrial arthropods group

Insect mouthparts represent modified arthropod appendages. This diversity of feeding devices provides numerous examples for the investigation of constraints and options in organ evolution. Our integrative approaches search for explanations of form-function relationships in the evolution of insect mouthparts in context with feeding techniques of flower-visiting insect.

Selected publications


Bauer B, Morawetz L, Ribarts A, Wüest R & Krenn HW. 2023. Impact of heat stress on flower visitation and pollination of Phaseolus coccineus by honey bees (Apis mellifera). Journal of Apicultural Research, DOI: 10.1080/00218839.2023.2277986 Link. Published online 29 November 2023

Barton S, Virgo J, Krenn HW. The Mouthparts of Female Blood-Feeding Frog-Biting Midges (Corethrellidae, Diptera). Insects. 2023; 14(5):461. Published online 13 May 2023


Reinwald C, Bauder JA-S, Karolyi F, Neulinger M, Jaros S, Metscher B, & Krenn HW. 2022. Evolutionary functional morphology of the proboscis and feeding apparatus of hawk moths (Sphingidae: Lepidoptera). Journal of Morphology, 1– 21. Published online 5 September 2022

Kuba K & Krenn HW (2022) Filtration of Nutritional Fluids in the German Wasp Vespula germanica (Vespidae, Hymenoptera). Insects. 2022; 13(2):185. Link. Published online 10 February 2022


Krenn HW, Karolyi F, Lampert P, Melin A, Colville JF (2021) Nectar Uptake of a Long-Proboscid Prosoeca Fly (Nemestrinidae)—Proboscis Morphology and Flower Shape. Insects. 2021; 12(4):371. Link. Published online 20 April 2021

Zenz K, Zettel H, Kuhlmann M & Krenn HW (2021) Morphology, pollen preferences and DNA-barcoding of five Austrian species in the Colletes succinctus group (Hymenoptera, Apidae). Deutsche Entomologische Zeitschrift 68(1): 101-138. Link. Published online 2 February 2021.


Pinterich E & Krenn HW (2020) Fruit-feeding behavior of the butterfly Consul fabius (Charaxinae, Nymphalidae, Lepidoptera). Entomologica Austriaca 27: 91–105. Link. Published online 14 March 2020


Krenn HW (Ed.) (2019) Insect Mouthparts Form, Function, Development and Performance Springer International Publishing

Krenn HW (2019) Introduction: Ecological Importance of Insect Feeding. In: Krenn HW (ed) Insect Mouthparts – Form, Function, Development and Performance. Zoological Monographs 5, Springer Nature Switzerland, pp. 1-7

Krenn HW (2019) Form and Function of Insect Mouthparts. In: Krenn HW (ed) Insect Mouthparts – Form, Function, Development and Performance. Zoological Monographs 5, Springer Nature Switzerland, pp 9-46

Krenn HW (2019) Fluid-Feeding Mouthparts. In: Krenn HW (ed) Insect Mouthparts – Form, Function, Development and Performance. Zoological Monographs 5, Springer Nature Switzerland, pp 47-99

Mauss V, Kuba K, Krenn HW (2019) Evolution of the Multifunctional Mouthparts of Adult Vespidae. In: Krenn HW (ed) Insect Mouthparts – Form, Function, Development and Performance. Zoological Monographs 5, Springer Nature Switzerland, pp 443-478

Shi L, Wu J, Krenn H, Yang Y & Yan S (2020). Temporal mode of fluid-feeding mechanisms in a long proboscid orchid bee compared to the short proboscid honey bee. Journal of Theoretical Biology 484: 110017 published online 19 September 2019,

Melin A, Krenn HW, Beale CM, Manning JC & Colville JF (2019) The allometry of proboscis length in Melittidae (Hymenoptera: Apoidae) and an estimate of their foraging distance using museum collections. PLoS ONE 14(6): e0217839, Published 7 June 2019

Düster JV, Gruber MH, Karolyi F, Plant J D, Krenn HW (2018) Drinking with a very long proboscis: Functional morphology of orchid bee mouthparts (Euglossini, Apidae, Hymenoptera). Arthropod Structure & Development 47, 25-35

Baranek B, Kuba K, Bauder JA-S, Krenn HW (2018) Mouthpart dimorphism in male and female wasps of Vespula vulgaris and Vespula germanica (Vespidae, Hymenoptera). Deutsche Entomologische Zeitschrift. 65(1): 65-74 doi: 10.3897

Savchenko E, Nicklas L, Milasowszky N, Krenn HW (2018) Zeitliche und räumliche Verteilung alpiner Tagfalter (Papilionoidea) entlang eines Höhengradienten in den Zillertaler Alpen (Österreich). Entomologica Austriaca 25: 25-49

Ivenz D. & Krenn HW (2017) Schwebfliegen-Gemeinschaften (Diptera: Syrphidae) im Nationalpark Gesäuse (Österreich). Entomologica Austriaca 24: 7-26

Krenn HW, Bauder JAS (2017) Morphological fine tuning of the feeding apparatus to proboscis length in Hesperiidae (Lepidoptera). Journal of Morphology 279 (3): 396-408.

Kreiderits A, Gamauf A, Krenn HW & Sumasgutner P (2016) Investigating the influence of local weather conditions and alternative prey composition on the breeding performance of urban Eurasian Kestrels (Falco tinnunculus). Bird Study/Ringing & Migration 1-12, available online

Krenn HW, Fournel J, Bauder J A-S & Hugel S (2016) Mouthparts and nectar feeding of the flower visiting cricket Glomeremus orchidophilus (Gryllacrididae). Arthropod Structure & Development 45 (2016) 221-229. available online

Karolyi F, Hansal T, Krenn, HW, Colville JF (2016) Comparative morphology of the mouthparts of the megadiverse South African monkey beetles (Scarabaeidae: Hopliini): feeding adaptations and guild structure. PeerJ 4:e1597
DOI 10.7717/peerj.1597

Hickel C, Gereben-Krenn B-A, Zweimüller I, Krenn HW (2016) Wetterbedingungen für die Erfassung von Tagfaltern (Lepidoptera: Papilionoidea) in alpinen -Lebensräumen in Österreich Entomologia Austriaca 23: 7-18. PDF

Bauder J, Morawetz L, Warren A, Krenn HW (2015) Functional constraints on the evolution of long butterfly proboscides: Lessons from Neotropical skippers (Lepidoptera: Hesperiidae) Journal of Evolutionary Biology 28: 678-687.
doi: 10.1111/jeb.12601

Bauder J, Warren A, Krenn HW (2015) The ecological role of extremely long-proboscid Neotropical butterflies (Lepidoptera: Hesperiidae) in plant-pollinator networks. Arthropod-Plant Interactions DOI 10.1007/s11829-015-9379-7

Barcaba T, Krenn HW (2015) The mouthparts of adult Indian meal moths, Plodia interpunctella (HÜBNER 1813) (Lepidoptera: Pyralidae). Entomologia Austriaca 22: 91-105.

Pass G, Tögel M, Krenn H, Paululat A (2015) The circulatory organs of insect wings: Prime examles for the origin of evolutionary noveties. Zoologischer Anzeiger 256: 82-95, available online.

Bossert, S, Gereben-Krenn, B-A, Neumayer, J, Schneller, B, Krenn, HW (2015) The cryptic Bombus lucorum complex (Hymenoptera: Apidae) in 1 Austria: Distribution, habitat usage and a climatic characterization based on COI sequence data. Zoological Studies 55: 13 (2016), doi:10.6620/ZS.2016.55-13.

Hölzl M, Gereben-Krenn B-A, Moser D, Krenn HW (2014) Bestandesrückgang der Mehlschwalbe (Delichon urbicum) in Wien: Resultate einer Bestandeserhebung im Jahr 2013. Vogelkundliche Nachrichten aus Ostösterreich 25: 10-20 

Sumasgutner P, Nemeth E, Tebb G., Krenn HW, Gamauf A (2014) Hard times in the city - attractive nest sites but insufficient food supply lead to low reproduction rates in a bird of prey. ─ Frontiers in Zoology 11:48.

Sumasgutner P, Schulze CH, Krenn HW, Gamauf A (2014) Conservation related conflicts in the nest-site selection of the Eurasian Kestrel (Falco tinnunculus) and the distribution of its avian prey. ─ Landscape and Urban Planning. doi:10.1016/j.landurbplan.2014.03.009.

Karolyi F, Colville JF., Handschuh S, Metscher BD, Krenn HW (2014) One proboscis, two tasks: Adaptations to blood-feeding and nectar-extracting in long-proboscid horse flies (Tabanidae, Philoliche). Arthropod Structure & Development 43: 403-413

Krenn HW, Bauder J A-S, Karolyi F, Gruber MH. 2014. Extremely long mouthparts in flower-visiting insects: form, function and evolution- Extrem lange Mundwerkzeuge blütenbesuchender Insekten: Form, Funktion und Evolution. Entomologisches Kolloquium 22.03.2014, Graz, Entomologica Austriaca 21: 241

Krenn HW, Bauder J A-S, Warren AD. 2014. World record holder in proboscis length of butterflies: the Neotropical skipper Damas immaculata (Hesperiidae). 7th International Conference on the Biology of Butterflies, August 11-14, 2014, Turku.

Bauder J A-S, Handschuh S, Metscher B D, Krenn HW (2013) Functional morphology of the feeding apparatus and evolution of proboscis length in metalmark butterflies (Lepidoptera: Riodinidae). Biological Journal of the Linnean Society, 110(2): 291-304. IF 2.413

Karolyi F, Morawetz L, Colville JF, Handschuh F, Metscher BD, Krenn HW (2013) Time management and nectar flow: flower handling and suction feeding in long-proboscid flies (Nemestrinidae: Prosoeca). Naturwissenschaften 100: 1083-1093, DOI 10.1007/s00114-013-1114-6. IF 2.144

Sumasgutner P, Krenn HW, Düesberg J, Gaspar T, Gamauf A. 2013. Diet specialisation and breeding success along an urban gradient: the kestrel (Falco tinnunculus) in Vienna, Austria. Beiträge zur Jagd und Wild 38 385-397.

Bauder J A-S, Krenn HW. La Gamba – ein Restaurant für Schmetterlinge. 2013. In: Roland A., Werner H., S.Pamperl, W. Wanek, A.Weber, A. Weissenhofer (eds) 20 Jahre Tropenstation La Gamba. Verein zur Förderung der Tropenstation La Gamba, Universität Wien, 80-81.

Krenn HW & Aspöck H (2012) Form, function and evolution of the mouthparts of blood-feeding Arthropoda. Arthropod Structure & Development 41 (2012) 101-118 

Wilhelmi AP & Krenn HW (2012) Elongated mouthparts of nectar-feeding
Meloidae (Coleoptera). Zoomorphology, (DOI) 10.1007/s00435-012-0162-3 

Bauder J, Lieskonig N, Krenn HW (2011) The extremely long-tongued Neotropical butterfly Eurybia lycisca (Riodinidae): Proboscis morphology and flower handling. Arthropod Structure & Development 40: 122-127

Gereben-Krenn B-A, Krenn HW, Strodl MA (2011) Initial Colonization of New Terrain in an Alpine Glacier Foreland by Carabid Beetles (Carabidae, Coleoptera). Arctic, Antarctic and Alpine Research 43, 397-403

Hikl A-L, Krenn HW (2011) Pollen processing behaviour of Heliconius butterflies: A derived grooming behaviour. Journal of Insect Science 11, Article 95, available online:

Gokcezade JF, Gereben-Krenn B-A, Neumayer J & Krenn HW (2010) Feldbestimmungsschlüssel für die Hummeln Österreichs, Deutschlands und der Schweiz (Hymenoptera, Apidae). Linzer biologische Beiträge 42/1, 5-42  

Krenn HW, Wiemers M, Maurer L, Pemmer V, Huber W, Weissenhofer A, Albert R (2010) Butterflies of the Golfo Dulce Region Costa Rica. Verein zur Förderung der Tropenstation La Gamba Costa Rica, pp 76.  

Sumasgutner P, Zuna-Kratky T & Krenn HW (2010) Einfluss der Waldstruktur auf die Nistplatzwahl von Greifvögeln in den March-Auen/Niederösterreich. Vogelwarte 48, 81-95.

Strodl MA, Gereben-Krenn BA, Huber C & Krenn HW (2010) Die Larven der alpinen Laufkäfergattung Oreonebria K. Daniel, 1903 in Österreich (Coleoptera: Carabidae). Contributions to Natural History 14: 1-20

Steinwender BM, Krenn HW, Wegensteiner R (2010) Different effects of the insectpathogenic fungus Beauveria bassiana (Deuteromycota) on the bark beetle Ips sexdentatus (Coleoptera: Curcullionidae) and on its predator Thanasimus formicarius (Coleoptera: Cleridae). Journal of Plant Deseases and Protection 117/1: 33-38  

Krenn HW (2010) Feeding mechanisms of adult Lepidoptera: structure, function, and evolution of the mouthparts. Annual Review of Entomology 55: 307-327 PDF

Eberhard SH, Hikl A-L, Boggs CL, Krenn HW (2009) Saliva or regurgitated nectar? What Heliconius butterflies (Lepidoptera: Nymphalidae) use for pollen feeding. Entomol Soc America 102/6: 1105-1108

Krenn HW,  Eberhard MJB,  Eberhard SH,  Hikl A-L, W Huber & Gilbert LE (2009) Mechanical damage to pollen aids nutrient acquisition in Heliconius butterflies (Nymphalidae) Arthopod-Plant Interactions 3/4: 203-208

Eberhard SH, Nemeschkal HL & Krenn HW (2009) Biometrical evidence for adaptation of the salivary glands to pollen-feeding Heliconius butterflies (Lepidoptera: Nymphalidae). Biological Journal of the Linnnean Society 97: 604-612

Karolyi F, Gorb SN & Krenn HW (2009) Pollen grains adhere to the moist mouthparts in the flower visiting beetle Cetonia aurata (Scarabaeidae, Coleoptera). Arthopod-Plant Interactions 3: 1-8

Krenn HW, Gereben-Krenn B-A, Steinwender BM, Popov A (2008) Flower visiting Neuroptera: mouthparts and feeding behaviour of Nemoptera sinuata (Nemopteridae). European Journal of Entomology 105: 267-277

Eberhard SH & Krenn HW (2008) Morphometry of the salivary glands in pollen-feeding butterflies of the genus Heliconius. Abstract Number: 644. XXIII International Congress of Entomology 2008 in Durban, South Africa, July 6-12 2008, p 420  

Krenn, HW (2008) Feeding behaviours of neotropical butterflies. In Weissenhofer A, Huber W, Mayer V, Pamperl, Weber A, Aubrecht G (Eds) Natural and Cultural History of the Golfo Dulce Region, Costa Rica, Stapfia 88 zugleich Kataloge der oberösterreichischen Landesmuseen Neue Serie 80, Biologiezentrum der Oberösterreichischen Landesmuseen, pp 295-304

Eberhard SH, Hrassnigg N, Crailsheim K, Krenn HW (2007) Evidence of protease in the saliva of the butterfly Heliconius melpomene (L.) (Nymphalidae, Lepidoptera). Journal of Insect Physiology 53: 126-131  

Hilgartner, R, Raoilison M, Büttiker W, Lees DC, Krenn WH (2007) Malagasy birds as hosts for eye-frequenting moths. Biology letters 3/2: 117-120. DOI:10.1098/rsbl.2006.0581

Krenn, HW (2007) Evidence from mouthpart Structure on internodial  relationships in Endopterygota? Arthropod Systematics & Phylogeny 65(1): 7-14

Schneider M, Krenn HW (2007) Nahrungsaufnahme von Acheta domesticus – Anleitung für ein Experiment im Biologieunterricht. Bioskop 2/2007: 34-40

Krenn HW (2007) In the butterfly restaurant. 5th International Conference on the Biology of Butterflies, Monte Porzio Catone (Roma) 2. – 7. 7. 2007

Strodl M, Gereben-Krenn B-A, Krenn, HW (2007) Block fields, stony debris formations and dolines as habitats of alpine arthropods - Evaluations of a new subterranean trap. Berichte des Naturwissenschaftlich-Medizinischen Vereins in Innsbruck  

Borrell BJ, Krenn HW (2006) Nectar feeding in long-proboscis insects. In Herrel A, Speck T & Rowe NP (eds) Ecology and Biomechanics: A mechanical approach to the Ecology of Animals and Plants, CRC Press LLC, 185-212  

Krenn HW (2006) Biodiversität neotropischer Tagfalter und die Vielfalt ihrer Nahrung. In Borsdorf A & Hödl W (Hg.) Naturraum Lateinamerika Geographische und biologische Grundlagen. Jahrbuch des Österreichischen Lateinamerika-Instituts Band 10, LIT-Verlag Wien, p 229-242  

Krenn HW, Plant J, Szucsich NU (2005) Mouthparts of flower-visiting insects. Arthropod Structure & Development 34: 1-40

Molleman F, Krenn HW, Van Alphen ME, Brakefield PM, DeVries, PJ, Zwaan BJ (2005) Food intake of fruit-feeding butterflies: evidence for adaptive variation in proboscis morphology. Biological Journal of the Linnean Society 86: 333-343.  

Eberhard S, Krenn HW (2005) Anatomy of the oral valve in nymphalid butterflies and model of fluid uptake of liquid food in Lepidoptera. Zoologischer Anzeiger 243: 305-312.  

Krenn HW,  Kristensen NP 2004 Evolution of proboscis musculature in Lepidoptera. European Journal of Entomology 101: 565-575

Pernstich A, Krenn HW (ed.)(2004) Die Tierwelt des Botanischen Gartens der Universität ein – Eine Oase inmitten der Großstadt. Institut für Angewandte Biologie und Umweltbildung, Wien  

Krenn HW, Weisert, F, Gereben-Krenn, B-A (2004) Die Schmetterlinge des Botanischen Gartens der Universität Wien. In Pernstich A, Krenn HW (Hsg.) Die Tierwelt des Botanischen Gartens der Universität ein – Eine Oase inmitten der Großstadt, p 121-133

Krenn HW, Gereben-Krenn, B-A (2004) Die Vögel des Botanischen Gartens der Universität Wien. In Pernstich A, Krenn HW (Hsg.) Die Tierwelt des Botanischen Gartens der Universität ein – Eine Oase inmitten der Großstadt, p 135-139

Eberhard S, Krenn HW (2003) Salivary glands and salivary pumps of adult butterflies (Nymphalidae, Lepidoptera). Zoomorphology 122: 161-167  

Pernstich A, Krenn HW, Pass G (2003) Preparation of serial sections of arthropods using 2,2-dimethoxypropane dehydration and epoxy resin embedding under vacuum. Biotechnic & Histochemistry 78: 1-5

Knopp MCN, Krenn HW (2003) Efficiency of fruit juice feeding in Morpho peleides (Nymphalidae, Lepidoptera). Journal of Insect Behavior 16: 67-77

Pellmyr O, Krenn HW (2002) Origin of a complex key innovation in an obligate insect-plant mutualism. Proceedings of the National Academy of Science 99/8: 5498-5502 PDF 

Krenn HW, Pernstich A, Messner T, Hannappel U, Paulus HF (2002) Kirschen als Nahrung des männlichen Hirschkäfers, Lucanus cervus (Linnaeus 1758)(Lucanidae: Coleoptera). Entomologische Zeitschrift 112/6: 165-170

Szucsich NU, Krenn HW (2002) Flies and concealed nectar sources: morphological innovations in the proboscis of Bombyliidae (Diptera). Acta Zoologica 83: 183-192  

Krenn HW, Mühlberger N (2002) Groundplan anatomy of the proboscis of butterflies (Papilionoidea, Lepidoptera). Zoologischer Anzeiger 241: 369-380 

Krenn HW, Mauss V, Plant J (2002) Evolution of the suctorial proboscis in pollen wasps (Masarinae, Vespidae). Arthopod Structure and Development 31: 103-120

Krenn HW, Schratt-Ehrendorfer L (2002) Transparente Plastikbeutel zur Untersuchung von Arthropoden. Entomologische Zeitschrift 112/11: 349-350 

Krenn HW, Zulka KP, Gatschnegg T (2001) Proboscis morphology and food preferences in Nymphalidae (Lepidoptera, Papilionoidea). Journal of Zoology, London 253, 17-26

Krenn HW, Kristensen NP (2000) Early evolution of the proboscis of Lepidoptera: external morphology of the galea in basal glossatan moths, with remarks on the origin of the pilifers. Zoologischer Anzeiger 239: 179-196

Krenn HW (2000) Proboscis musculature in the butterfly Vanessa cardui (Nymphalidae, Lepidoptera): settling the proboscis recoiling controversy. Acta Zoologica Stockholm 81: 259-266

Szucsich NU, Krenn HW (2000) Morphology and function of the proboscis in Bombyliidae (Diptera, Brachycera) and implications for proboscis evolution in Brachycera. Zoomorphology 120: 79-90

Penz CM, Krenn HW (2000) Behavioral adaptations to pollen-feeding in Heliconius butterflies (Nymphalidae, Heliconiinae): an experiment using Lantana flowers. Journal of Insect Behavior 13: 865-880

Gereben-Krenn B-A, Krenn HW (2000) Living at the edge of ice: carabid beetles in an alpine glacier foreland. In: Gazzoni DL (Ed). XXI International Congress of Entomology, Brazil, August 20-26, 2000, Abstracts of International Congress of Entomology Londrina Brazil: Embrapa Soja, 2000. Vol 2: 902  

Krenn HW, Gereben-Krenn B-A (1999) Saatkrähen (Corvus frugilegus L.) im Winter 1998/99 in Wien. Vogelkundliche Nachrichten aus Ostösterreich 10: 49-51

Krenn HW (1998) Proboscis sensilla in Vanessa cardui (Nymphalidae, Lepidoptera) - functional morphology and significance in flower-probing. Zoomorphology. 118: 23-30

Krenn HW, Penz CM (1998) Mouthparts of Heliconius butterflies (Lepidoptera: Nymphalidae): a search for anatomical adaptations to pollen-feeding behaviour. International Journal of Insect Morphology & Embryology 27: 301-309

Krenn HW (1997) Proboscis assembly in Lepidoptera - a once in a lifetime sequence of events. European Journal of Entomology 94: 495-501

Wolf B, Krenn HW, Gereben-Krenn B-A (1997) Der Bestand der Saatkrähen (Corvus frugilegus L. 1758) an den großen Winterschlafplätzen in Wien 1996/97. Vogelkundliche Nachrichten aus Ostösterreich 8: 71-74

Paulus HF, Krenn HW (1996) Vergleichende Morphologie des Schmetterlingsrüssels und seiner Sensillen - Ein Beitrag zur phylogenetischen Systematik der Papilionoidea (Insecta, Lepidoptera). Journal of Zoological Systematics and Evolutionary Research 34: 203-216

Büttiker W, Krenn HW, Putterill J (1996) The proboscis of eye-frequenting and piercing Lepidoptera. Zoomorphology 116: 77-83

Gereben B-A, Wolf B, Krenn HW (1995) Der Bestand der Saat­krähen (Corvus frugilegus L. 1758) an den großen Winter­schlafplätzen in Wien 1994/95. Vogelkundliche Nachrichten aus Ostösterreich 6/2: 43-46

Krenn HW, Pass G (1994) Morphological diversity and phylogenetic analysis of wing circulatory organs in insects, part 1: Non-Holometabola. Zoology 98: 7-22.

Krenn HW, Pass G (1994/1995) Morphological diversity and phylogenetic analysis of wing circulatory organs in insects, part 2: Holometabola. Zoology 98: 147-164

Krenn HW (1993) Postembryonic development of accessory wing circulatory organs in Locusta migratoria (Orthoptera: Acridiidae). Zoologischer Anzeiger 230: 227-236

Krenn HW, Pass G (1993) Wing-hearts in Mecoptera (Insecta). International Journal of Insect Morphology & Embryology 22: 63-76

Krenn HW, Gereben B-A, Wolf B (1993) Der Bestand der Saatkrähen(Corvus frugilegus) an den Winterschlafplätzen in Wien 1992/93. Vogelkundliche Nachrichten aus Ostösterreich 4/3: 85-89

Krenn HW (1991) Der Winterschlafplatz der Saatkrähen (Corvus frugilegus) auf der Baumgartner Höhe in Wien. Vogelkundliche Nachrichten aus Ostösterreich 2/3: 1-7

Krenn HW (1990) Functional morphology and movements of the proboscis of Lepidoptera (Insecta). Zoomorphology 110: 105-114