B.ungurean - THE COMPLEX OF ENTOMOPHAGOUS SPECIES LIMITING THE POPULATIONS OF SOME COLEOPTERANS...

8/9/2019 B.ungurean - THE COMPLEX OF ENTOMOPHAGOUS SPECIES LIMITING THE POPULATIONS OF SOME COLEOPTERANS …

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Analele Știin țifice ale Universității „A l. I. Cuza ” Iaș i, s. Biologie animală, Tom LVI, 2010

THE COMPLEX OF ENTOMOPHAGOUS SPECIES LIMITINGTHE POPULATIONS OF SOME COLEOPTERANS HARMFUL TO

WOODEN PATRIMONY TREASURES EXPOSED IN NATURE

Bogdan UNGUREANAlexandru Ioan Cuza University, Faculty of Biology, Bd. Carol I 20A, 700505 Iași, Romania,

[email protected]

Abstract. In the paper we present the trophic relationships that are established among some xylophagouscoleopterans and the complex of entomophagous species, reported in our researches, which acts as a limitingfactor in their development. The researches were accomplished in the period 2007-2009 on patrimony objects

from the ethnographic collection of the Astra Museum in Sibiu, made of wood and exposed in nature, attacked by xylophagous coleopterans. The analyzed material is part of the research project within the PhD thesis onconservation of wooden patrimony attacked by xylophagous insects.

Keywords: i nsects, coleopterans, entomophagous species, patrimony, biodegradation.

Rezumat. Complexul de entomofagi care limitează populaț iile unor coleoptere dăunătoare bunurilor depatrimoniu din lemn expuse in natură . În lucrarea de față prezentăm relațiile trofice care se stabilesc întreunele specii de coleoptere xilofage și complexul de entomofagi, semnalat în cercetările noastre, care acționeaz ăca factor limitativ în dezvoltarea acestora. Cercetările au fost efectuate în perioada 2007-2009 pe obiecte de

patrimoniu din colec ția etnografică a muzeului Astra din Sibiu, confecționate din lemn și expuse în natură,atacate de coleoptere xilofage. Materialul analizat este parte din proiectul de cercetare ce face obiectul tezei dedoctorat pe tema conservării bunurilor de patrimoniu din lemn atacate de insecte xilofage.

Cuvinte cheie: insecte, entomofagi, coleoptere, patrimoniu, biodegradare.

IntroductionPatrimony treasures made of wood and exposed outdoors are part of the national

cultural patrimony not only with historical importance, but also artistic and ethnographic.The cataloguing of an object as good of patrimony, made of wood, involves mostly acertain age of the respective object, which confers a value in addition, historically andartistically. Direct consequence of passing through time of the object constituent matter(wood), is its antiquation, a phenomenon which in general includes the degradation andimplicitly the original matter biodegradation. Thus, the woody matter constitutes thetrophic basis for different samples of bio pests that succeed in different intervals,correlated with the degree of depreciation of the nutrient substrate.

The wood involved in the patrimony treasures exposed outdoors represents theecological niche for different species of xylophagous insects belonging to the orderColeoptera, which develops attacks placed at intervals whose cumulative effects resultingin advanced damage to the wooden matter. From the point of view of ecological, certainrelationships appear between the xylophagous insects and decay species ofmicroorganisms (bacteria and fungi), which determine interdependent phenomena actingsimultaneously on the nutritive substrate. Bacteria and fungi have a role in degradation ofcellulose from the wood, favoring its consumption by the xylophagous insects. Secondtypes of trophic relationships which emerge are those which can be realized between thexylophagous coleopterans and the complex of entomophagous species that limit the

populations of the first group mentioned. In our researches we followed the xylophagous pests reported on the patrimony treasures manufactured of wood and exposed in nature,

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Bogdan Ungurean

having as main stationary points the ethnographic collections of the museums in the open,

“Astra ” in Sibiu and “D Gusti ” in Bucharest. This paper aims at reporting the ecologicalcorrelations between the entomoparasite insects and those xylophagous ones, harmful toethnographic museums in open air. The researches to which the present material makesreference were carried out at the “ASTRA Traditio nal Popular Civilization Museum” inSibiu.

Materials and Methods Xylophagous insect collectings were made mainly by two methods: direct

collecting during the hatching period of adults and by the utilization of adhesive trapswithout attractants. The parasitoid species were obtained directly from the hosts, whichwere collected on yellow sticky traps. The traps were placed on pieces from the museumwhich were representing the active attack of the xylophagous coleopterans, the exposure

period of the traps being from spring until late autumn (2007-2009), when it ends the

activity of the last echelon of adults of xylophagous insects of the generation in thatrespective year.

a b

c dFigure 1. a, b, c, d. Aspects of the adhesive traps placed in the museum.

Extraction of the individuals from the traps was made by immersion in xylenesolution (the adhesive of the traps being soluble in hydrocarbons from the group of thosearomatic), subsequently being passed through washing successive baths with xylene toremove the largest possible proportion of glue. Preparation for the exhibition, for theidentification respectively, was made by passing of insects through isobutilic alcohol

baths (intermediate between hydrocarbon and the group of alcohols), and finally ethylicalcohol - a conservation medium for the collected individuals. The identification ofxylophagous coleopterans was performed by the author on the basis of keys foridentification specific to groups of insects involved in the degradation of the wood(Mustață, 1998, 2001),and the identification of the parasitoid species were made byspecialists on groups within the entomology laboratory of the Zoology Department of theFaculty of Biology using several identification keys (Achterberg, 1993; Belokobylskij &Taeger, 2001; Hickin Norman, 1963; Lăcătușu & Filipescu, 1989; Tobias, 1995, 1996).The elucidation of the host-parasitoid relationships was realized on the basis of theinformation mentioned in the scientific literature – catalogues, monographs ( Pisică, 2001),and through individual observations made in nature and in laboratory.

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Results and Discussions

The species of xylophagous insects reported belong to five families of the orderColeoptera: Anobiidae, Cerambycidae, Lyctidae, Curculionidae and Ptinidae. The share,in which individuals of the different species from the mentioned families arerepresentated, is different. The representatives of the family Anobiidae are dominant,constant and euconstant species. In Table 1, the main species of xylophagous insectsreported as pests on the patrimony treasures from the museum in which I conductedresearches.

Table 1. The main insect species reported as pests of the patrimony treasures manufactured of woodand exposed in nature.

Family SpeciesAnobiidae Anobium punctatum (De Geer)

Xestobium rufovillosum (De Geer) Ptilinus pectinicornis (Linnaeus)

Ernobius mollis (Linnaeus)Cerambycidae Hylotrupes bajulus (Linnaeus)Lyctidae Lyctus linearisi (Goeze)Curculionidae Rhyncolus (Stereocorynes) truncorum (Germar)

In our researches there were also determined thirteen parasitoid taxa whoseactivity is correlated with the species of xylophagous insects among the reported species.The parasitoid insects belong to four families of the order Hymenoptera: Ichneumonidae,

Braconidae, Pteromalidae and Scelionidae. Of these ten are parasitoids of some speciesof xylophagous insects, one species is parasite on the eggs of coleopterans and the othertwo are hyperparasitoids of the first category mentioned. In Table 2, there are presentedthe entomoparasite species collected with the help of traps placed in the stationary.

Table 2. The parasitic entomofauna reported in our researches. HYMENOPTERA

ICHNEUMONOIDEAICHNEUMONIDAE

PIMPLINAE Liotryphon crassiseta Thomp. Ephialtes planifrons Ephialtes spp.

POEMENIINAE Neoxorides collaris Grav. Deuteroxorides spp.

MESOCHORINAE Mesochorus facialis Bridgm. Mesochorus anomalus Holmgr.

BRACONIDAEHELCONINAE

Aspicolpus erythrogaster Tobias DORYCTINAE

Spathius exarator L. Hecabolus sulcatus Curt.

CHALCIDOIDEA PTEROMALIDAE PTEROMALINAE

Trichomalus helvipes Walk. Lariophagus distinguendus Foerst.

PLATYGASTROIDEA SCELIONIDAE

Trimorus spp.

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Bogdan Ungurean

Figure 2. Graphic representation of the trophic relationships among the species harmful to patrimony treasures and entomophagous species.

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Trophic relationships that can be established between the parasitic entomofauna

and xylophagous insects harmful to patrimony treasures are shown in Figure 2.The species of parasite insects identified have a different proportion of incidencein relation to xylophagous coleopterans (Fig. 3). It may be evident in this respect the

presence in a greater proportion in comparison with other families of the species from thefamily Braconidae , these being those that hold the share of the parasitic trophicrelationships on xylophagous coleopterans.

BRACONIDAEDORYCTINAE ICHNEUMONIDAESpathius exarator PIMPLINAE PTEROMALIDAE

Hecabolus

sulcatus

POEMENIINAE SCELIONIDAE

Figure 3. Graphical representation of the incidence share of the main families / subfamilies ofentomophagous species in relation to xylophagous insects.

ConclusionsPatrimony treasures made of wood and exposed in nature are attacked in

different stages by a varied number of xylophagous coleopterans.The attacks of the different groups of insects are placed at intervals according to

nutritive preferences depending on the type of the wooden essence, age and the state of itsdegradation.

On the older degraded wood, (subject to the initial action of fungi), ischaracteristic the presence in larger proportion of the xylophagous insects of the third

echelon - Anobiidae, Lyctidae (Powder Post Beatles) and others.The species of dominant, constant and euconstant xylophagous coleopterans arethose belonging to the family Anobiidae ( Anobium punctatum De Geer, Xestobiumrufovillosum De Geer, Ptilinus pectinicornis Linnaeus) characterized by a broad

polyphagous trophic spectrum.The exposure to the outside environment of the attacked patrimony treasures

facilitates the emergence of a complex of parasitoids that acts as a limiting factor in thedevelopment of populations of xylophagous coleopterans.

In our researches we have reported so far a number of thirteen taxa of parasitoidsthat are in trophic relationships with species of xylophagous coleopterans present on the

patrimony treasures that belong to four families of the order Hymenoptera: Ichneumonidae, Braconidae, Pteromalidae and Scelionidae.

Among the taxa mentioned ten are parasitoids of the larvae of xylophagous

insects being reported also cases of hyperparasitoids.Among the insects of the entomophagous complex reported, the species belonging to the family Braconidae are those with the highest incidence on the harmfulxylophagous coleopterans identified by us.

AcknowledgementsMany thanks to Prof. Dr. Gheorghe Musta ță, Prof. Dr. Ionel Andriescu, Prof. Dr.

Constantin Pisică,Lecturer Dr. Ovidiu Popovici, and PhD student Cătălin Ailenei foridentifying the entomophagous species.

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