ZOBODAT - www.zobodat.at Zoologisch-Botanische Datenbank/Zoological-Botanical Database Digitale Literatur/Digital Literature Zeitschrift/Journal: Bonn zoological Bulletin - früher Bonner Zoologische Beiträge. Jahr/Year: 2005/2006 Band/Volume: 54 Autor(en)/Author(s): Schmitt Michael, Bopp Sigrun Artikel/Article: Leaf Beetles (Insecta: Coleoptera: Chrysomelidae) - Suffer From Feeding on Fern Leaves 261-269 © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zoologicalbulletin.de; www.biologiezentrum.at Bonner zoologische Beiträge Band 54(2005) Heft 4 Seiten 261-269 Bonn, Oktober 2006 Leaf Beetles (Insecta: Coleóptera: Chrysomelidae) Suffer From Feeding on Fern Leaves' 2 Michael SCHMITT ' & Si srun BOPP 2) Zoologisches Forschungsmuseum Alexander Koenig, Bonn, Germany Universität Ulm, Abteilung Systematische Botanik und Ökologie, Ulm, Germany Abstract. Two age groups of larvae of Agelastica alni (Linnaeus, 1 758) and Phratora vitellinae (Linnaeus, 1 758) were provided with treated or untreated leaves of their actual host plant (Alnus glutinosa or Salix spp., respectively) or of the ferns Aihyrium filix-femina, Diyopleris austriaca and D. filix-mas. "Treated" leaves were covered with an aqueous ex- tract of host plant or fern leaves. Mortality of young larvae (one-day old) of A. alni was significantly higher when pro- vided with treated or untreated fern leaves and treated food plant leaves compared to untreated food plant leaves. Mor- tality of older larvae (six-day old) was significantly lower than that of young larvae. Young larvae did not feed on fern leaves at all, while older larvae ingested material from treated fern leaves, however at low rates. Phratora vitellinae in- dividuals showed abnormal elytra and irregular melanisation patterns when they had taken up fern substances. In both species, the larvae produced less defensive secretion if they had ingested an extract of Athyrium filix-femina. Key words. Agelastica alni, Phratora vitellinae, Filicatae: Aspidiaceae. phytophagy, larval development 1. INTRODUCTION Data from bracken (e.g., Martins et al. 1995; Gilman & Cooper-Driver 1998) can be generalised only with There are 12,500 species of ferns and 230,500 species care since this fern species is ( 1 ) certainly the most of seed plants (Speck 1992). Some 140,000 species of abundant fern species on earth, and (2) is regarded a Phytophaga (= Pseudotetramera = Curculionoidea + pest since it causes illness to cattle when fed. Thus, Cerambycidae + Bruchidae + Chrysomelidae; Lexikon bracken is definitively the most intensively studied fern der Biologie, Urania-Tierreich) mean a proportion of species. one species of pseudotetramerous beetles per 1.7 species of spermatophyte plant, but only 105 species of Phyto- In other taxa, for example, Lithinine moths, there might phaga are known to feed on ferns (Balick et al. 1978), have been a phylogenetic adaptation towards fem feed- producing a proportion of 1:119.0. According to ing (WEINTRAUB et al. 1995). The sawfly Strongy- HENDRIX (1980) of 726,000 species of insects known at logaster osmundae (Takeuchi, 1941) (Hymenoptera: that time, 338,000 are phytophagous (1:0.7), but only Tenthredinidae) develops obligatorily on the osmund 465 feed on ferns (1:26.9). Of the 413 arthropod species fem, Osmunda japónica. In leaf beetles, however, there reported as found on ferns, 93 attack bracken (Pteridium is no indication that any species is especially adapted to aquilinum) exclusively, making the proportion 1:33.3. the exploitation of this food resource. For example. Even if these numbers must be corrected for uneven WlNTERBOURN (1987) found beetles of seven families numbers of individuals or/and different availability of on bracken, amongst them no leaf beetles, a result also biomass, it is clear that there are much less leaf beetles supported by Mesibov (2001). Mukhopadhyay & (Chrysomelidae) feeding on ferns than could be ex- Thapa (1994) list 19 beetle species, among them seven pected according to species numbers. There might be species of Chrysomelidae as "associated with ferns", regional exceptions (e.g., Veracruz, Mexico: BALICK et however without providing any information as to the in- el. 1978; Hawaii: Swezey 1922). Especially arthropods tensity of this "association". Since among the seven leaf with chewing mouthparts are remarkably underrepre- beetles listed by MUKHOPADHYAY & THAPA there is sented on ferns as compared to the large percentage of also Aspidimorpha sanctaecrucis (Fabricius, 1792), insects with sucking mouthparts (Thysanoptera, Heter- which is definitely restricted to Convulvulaceae (GHATE optera, Homoptera; HENDRIX 1980; Hill 1998; D'Ro- et al. 2003), one should draw conclusions very cau- ZARIO& BERA 2003). tiously. Possible reasons for the strikingly lower number of phytophagous beetles on ferns than on angiosperms th could be that ferns are either toxic, or have repellents, or Paper presented to the 6 International Symposium on the Chry- somelidae, Bonn, Germany, May 7, 2004. lack attractants. © Biodiversity Heritage Library, http://www.biodiversitylibrary.org/; www.zoologicalbulletin.de; www.biologiezentrum.at 262 Bonner zoologische Beiträge 54 (2005) In order to shed some light on these questions for three mortality were registered on day 3, 8, and 10 after the species of Central European ferns {Athyriumfilix-femina beginning of the experiment. (Lady Fern), Dryopteris austriaca (Wood Fern) and D. Adults of Phratora vitellinae were collected from wil- filix-mas (Male Fem), we conducted feeding experi- lows and poplars growing in a park area on the outskirts ments with two species of leaf beetles, Agelastica alni of Freiburg im Breisgau. They were kept and treated as (Linnaeus, 1758) and Phratora vitellinae (Linnaeus, the individuals of Agelastica alni. However, since con- 1758). siderably less larvae of Phratora vitellinae could be ob- tained, meaningful statistical analysis was not possible. 2. MATERIALS AND METHODS Leaves of Athyrium filix-femina, Diyopteris austriaca Fifteen adult individuals of Agelastica alni were col- and D. filix-mas were collected in a forest close to the lected from Common Alder {Abuts glutinosa) in the sur- city of Freiburg im Breisgau ("Sternwald"), always roundings of Freiburg im Breisgau, Germany. They from the same area. Aqueous extracts were made from were kept in plastic containers on a layer of gypsum and fresh leaves and from those dried for four weeks at fed with fresh alder leaves. Their eggs were collected room temperature. The leaves were put into tab water and the hatched larvae were fed on fresh leaves of their for 30 minutes and then squeezed with broad forceps in original food plant until they were used in the tests. We order to gain not only water-soluble but also lipophilous conducted two series of tests: (1) with "young" - i.e., substances. The test leaves were soaked with the respec- freshly hatched - larvae, and (2) with "old" - i.e., six- tive extracts for 30 minutes in order to mask their con- day old - larvae. In both age groups feeding traces and tact chemical properties. Table 1. Experimental Settings _Test Number kind of Food Offered 1 Normal food plant (f.p.) masked with extract from dried Dryopteris filix-mas (D.f.) 2 Normal food plant (f.p.) masked with extract from dried Dryopteris ausriaca (D.a.) 3 Normal food plant (f.p.) masked with extract from dried Athyrium filix-femina (A.f.) 4 Dried D. filix-mas masked with extract from the normal food plant 5 Dried D. austriaca masked with extract from the normal food plant 6 Dried A. filix-femina masked with extract from the normal food plant 7 Dried D. filix-mas, swelled in tab water 8 Dried D. austriaca, swelled in tab water ( ) Dried A. filix-femina, swelled in tab water 10 Dried normal food plant, swelled in tab water I I Normal food plant masked with extract from fresh Dryopteris filix-mas 12 Normal food plant masked with extract from fresh Diyopteris ausriaca 13 Normal food plant masked with extract from fresh Athyrium filix-femina 14 Fresh D. filix-mas masked with extract from the normal food plant 15 Fresh D. austriaca masked with extract from the normal food plant 16 Fresh A. filix-femina masked with extract from the normal food plant 17 Fresh D. filix-mas, swelled in tab water 18 Fresh D. austriaca, swelled in tab water 1') Fresh A. filix-femina, swelled in tab water 20 Fresh normal food plant, swelled in tab water 21 Fresh D. filix-mas, untreated 22 Fresh D. austriaca, untreated 23 Fresh A. filix-femina, untreated 24 Fresh normal food plant, untreated For each of the two test series 24 setups were designed. leaves of their food plant, the initiation of their pupation The details are given in Table 1 . The test larvae were can be observed directly. kept under the described conditions until either all were dead or the first individuals tried to pupate (which can We used the Statistical Package for Social Sciences easily be recognised as Agelastica alni beetles pupate in (SPSS) to calculate a logistic regression. Probabilities of the soil. Thus, larvae ready to pupate attempt at digging error were calculated by Chi- or Fisher's exact test (the 2 holes in the gypsum). 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