Ian W. B. Thornton

Colonisation of the Krakatau islands by invertebrates

Arrival of invertebrates on the Krakatau islands, and the development of invertebrate assemblages there since 1883, are reviewed. Many data are imprecise, and difficulties of interpretation are outlined. A few well-known groups, such as butterflies, are used to suggest that much colonisation so far has been by relatively generalist species,and that the rate of addition of new species may become slower as the less vagile specialists characteristic of later successional vegetation may find natural colonisation harder. Studies of the assemblages developing in association with particular plant species are likely to be helpful in assessing future trends of invertebrate colonisation.

Anak Krakatau — a colonization model within a colonization model?

AbstractThe ppaer re-examines three suggestions previously made concerning the colonization of the Krakatau islands since the extirpating 1883 eruption that involve the more recently emergent volcanic island Anak Krakatau, which itself suffered a devastating eruption in 1952. The suggestions re-addressed in the light of recent comments by other workers are: (1)Anak Krakatau offers, in general terms, an analogy of the early successional processes that occurred on the three older islands in the first decades after the 1883 extirpating eruption.(2)Anak Krakatau (with the Sertung spit) may have acted as an ecological refuge for open country species whose habitat on the three older islands declined as a result of vegetation succession.(3)Mainland open country species that did not colonize the archipelago when the appropriate vegetational successional stage occurred on the three older islands may now do so through a reopened early-successional window — Anak Krakatau (and the Sertung spit). Mann-Whitney tests carried out on species naturally colonizing the Krakatau group and those colonizing Anak Krakatau since its self-devastating eruption of 1952 showed that in the case of spermatophytes, pteridophytes and resident land birds, the biota available on the older islands has contributed to Anak Krakataus developing biota with a bias towards species that arrived on the archipelago early. There are indications also for reptiles, frugivorous birds, bats and figs that successful colonists of Anak Krakatau from the older islands tend to have been early colonists to the archipelago also. For butterflies, however, Mann-Whitney does not indicate strong correspondence between early arrival on the archipelago and occurrence on Anak Krakatau. The butterfly fauna is ecologically strongly disharmonic, heavily biased towards species of coastal and near-coastal habitats and the coastal flora of the archipelago has changed little since 1897, Anak Krakataus flora comprising almost entirely such species. On both the archipelago and Anak Krakatau, over similar periods since their sterile beginnings, the proportion of marine-dispersed plant colonists has steadily declined and the animal-dispersed fraction increased. Thus in two aspects of colonization — order of species arrival and changes in dispersal mode spectra of plants, the colonization of Anak Krakatau from the older islands has been analogous to that of the older islands from the mainland in the first decades after 1883.Differences between the two models are: the presence of close sources, the early availability of animal dispersers of plants in the case of Anak Krakatau, and continuing volcanism. The second of these may explain the significant proportion of animal-dispersed taxa in the early plant colonists of Anak Krakatau after 1930 but not of the archipelago after 1883. Volcanism has affected Anak Krakataus biotic development sporadically since its birth and eruptions in 1972/3 probably constrained increase in species numbers and seriously set back plant succession. In contrast, the archipelagos biotic development has been affected only at a later stage in the process, and with different effects on different islands.Evidence is advanced that Anak Krakatau (with the Sertung spit) may have acted as an ecological refuge for some 18 open country animal species of which the preferred habitat on the older islands was gradually extirpated as a result of successional processes, and as a respening ealry-successional window for as many as 12 earl-successional mainland animal colonists, for which the window of opportunity on the older islands had become closed by succession to mixed forest.

The systematics, phylogeny and biogeography of the psocopteran family Philotarsidae

The 150 or so species of the Philotarsidae are reviewed. Using up to twenty‐six characters from 107 species, principal coordinates analyses are undertaken and groupings recognized. Inadequately known species are placed, on known characters, into the groups revealed by the analysis. Where appropriate, generic transfers are made. A revised classification is proposed and two subfamilies recognized: Philotarsinae (containing the tribes Philotarsini and Aaroniellini) and Zelandopsocinae. A new genus, Latrobiella, is erected and Broadheadia is reduced to a synonym of Aaroniella. A key to genera is given. Four new species are described and additional descriptions given for several others. A possible phylogeny of the family is suggested and the geographical distribution of groups is discussed in relation to the possible historical roles of fragmentation and dispersal.

Psocomorpha (Psocoptera) from the Malayan Peninsula

Abstract Recent collections of Psocomorpha (Psocoptera) from the Malayan Peninsula and Singapore are enumerated. Twenty seven new species are described and figured, belonging to Epipsocidae (10), Caeciliidae (2), Amphipsocidae (1), Pseudocaeci- liidae (3), Philotarsidae (1), Peripsocidae (4), Myopsocidae (2) and Psocidae (4). Illustrated redescriptions of the types of Epipsocus prominens Banks, E. Hyalinus Banks, E. fumlpennis Banks and Allopsocus marginalia Banks are given. E. Fumlpennls and E. Hyalinus are transferred to Epipsocopsis Badonnel, and Allopsocus Banks placed in the Pseudocaeciliidae. Records are given of 9 other earlier described species, and of unidentified species of Mesopsocidae (1), Caeciliidae (5) and Archipsocidae (1).

Photographic evidence of rate of development of plant cover on the emergent island Anak Krakatau from 1971 to 1991 and implications for the effect of volcanism

Photographs of the vegetated North and East Forelands of Anak Krakatau, which emerged from the sea in 1930 and was totally devastated by volcanic activity in 1952/53 provide some evidence of rate of change of plant cover from grassland to woodland between 1971 and 1991. The series of photographs demostrate that vegetational stages of the two forelands have not been synchronous and suggest that the North Foreland is lagging the East Foreland by about 12 years.A recent hypothesis that Anak Krakataus vegetation was destroyed, totally or almost so, by eruptions in 1972/73 and the islands vegetation has regenerated since that time is not easily accommodated by the photographic evidence, nor by the relative rates of change on Rakata (Krakataus post-1883 remnant) and Anak Krakatau. The photographic evidence accords more closely with a hypothesis that the 1972/73 eruptions affected the North Forelands vegetation only, or affected it to a much greater degree than that of the East Foreland, allowing the latters post-1952/53 succession to proceed relatively unhampered.

Phylogeny and distribution of the phoracanthine genus Atesta (Coleoptera: Cerambycidae) from Australia

The phylogeny of the phoracanthine genus Atesta (thirty‐four species) is analysed using cladistic methods. The monophyly of Atesta is confirmed. Three major monophyletic species groups are recognized: (1) the thorntoni‐group including twelve species: A.thorntoni, A.balteata, A.latifasciata, A.mediana, A.patula, A.newi, A.angasi, A.bifasciata, A.besti, A.ciliata, A.paratasmanica and A.tasmanica; (2) the sisyrioides‐group consisting of seventeen species: A.ibidionoides, A.carteri, A.longoelytrata, A.pubescens, A.stigmosa, A.sita, A.vittata, A.sparsa, A.minuta, A.tropicalis, A.unifasciata, A.sisyrioides, A.nigrihumerus, A.apicalis, A.brittoni, A.antennalis and A.brooksi, and (3) the houstoni‐group containing five species: A.mapida, A.houstoni, A.tripartita, A.dixoni and A.centroaustralica. The distribution patterns of Atesta are described and discussed. Five distinct areas of endemism are found for Atesta: the Torresian, Timorian, Kosciuskan, Western and Eyrean Subregions. The Torresian Subregion has nine species, three of which are endemic to the subregion; the Timorian has four species, two of which are endemic; the Kosciuskan has twenty‐three species, sixteen of which are endemic, the Western has five species, four of which are endemic, and the Eyrean has three species, one of which is endemic. Two kinds of distribution patterns for Atesta are identified: the wet adapted (peripherial), including the thorntoni‐group and sisyrioides‐group, and the wide‐adapted, consisting of the houstoni‐group. The thorntoni‐group is typically a southern Australian species group, distributed in south‐eastern and south‐western Australian continent and Tasmania. The sisyrioides‐group is mainly distributed in southeastern, eastern and northern Australian continent and Tasmania. The distribution of the houstoni‐group includes central and peripherial Australian continent.

Systematics of the Calopsocidae, an oriental and melanesian family of Psocoptera

Abstract. As here revised, the family Calopsocidae comprises the genera Calopsocus Hagen (seventeen species), Neurosema McLachlan (seven), Callistoptera Enderlein (one) and Nemupsocus New (one), and four newly erected genera, Calosema (one species), Cyclopsocus (five), Dendropsocus (one) and Torrepsocus (two). A key to genera is provided, and keys to species of Calopsocus, Cyclopsocus and Neurosema. Ten species of Calopsocus are described, one of Calosema, four of Cyclopsocus, one of Dendropsocus, three of Neurosema and one of Torrepsocus. The type species of Dirla, D.javana Navas, is redescribed, and Dirla is synonymized with Calopsocus. Dirla furcata New is transferred to Calopsocus, Dirla navasi New to Cyclopsocus and Dirla pulleni Smithers to Torrepsocus. Calopsocus irretitus (Navas) is synonymized with Calopsocus rizali Banks. Further descriptions are provided of Callistoptera anna Enderlein, Calopsocus guttatus Smithers, Calopsocus iridescens Banks, Cyclopsocus navasi (New), Neurosema apicalis McLachlan and Torrepsocus pulleni (Smithers). The range of Calopsocus extends from Ceylon to New Caledonia, with ten species occurring in New Guinea; the remaining genera, including the most primitive, Cyclopsocus, are confined to New Guinea, where there has been considerable radiation, except that one species of Neurosema is recorded from the Philippines.

A Numerical Taxonomic Analysis of the Peripsocidae of the Oriental Region and the Pacific Basin

The relationships of 83 species of psocids of the family Peripsocidae (Insecta: Psocoptera) were analysed numerico-taxonomically, using alternative methods of processing. The results of using different sets of adult morphological characters and different combinations of them were compared. The effect of admitting a large number of species with incomplete data (known from one sex only) into the system was investigated. Certain modifications of the accepted classification of the family were suggested. Numerical taxonomy was developed to provide an objective and repeatable method of evaluating the phenetic affinity between taxonomic units (see Sokal and Sneath, 1963). The method rests on the hypothesis that there are no special groups of genes the effects of which are confined to single mQrphological regions, and that a random sample of the genotype is best obtained by sampling many and various characters. A large number of characters is used and each character is considered to be of equal weight, and the larger the number of characters used, the more stable is the value of the overall similarity coefficient, up to an asymptote which will vary for each analysis. Rohlf (1963) used numerical taxonomic methods to compare the classification of Aedes using only adult characters with that using only larval characters and found a definite though low correlation between the resulting classifications. In 1963 Sokal and Michener (see Rohlf, 1963) compared the results of classifications based on female and male, and on head and non-head characters, and found similar values of correlation. In the study reported here species with incomplete data (known from one sex only) are admitted to the analysis by degrees, and the effect of these admissions on the classification based on individuals with information on both sexes is noted. Also, different sets of characters are omitted in different analyses and the results compared. Alternate methods in the processing of data are used, in order to find the combination best suited for the classification of Peripsocidae. MATERIAL AND METHODS General.-Eighty-three species of the family Peripsocidae representing three of the five genera were examined, using numerical taxonomic methods. Previously described species of which examples were unobtainable were not included in the study, due to reason which will be obvious later. A preliminary survey was run to find some 60 characters that vary among species (Sokal and Sneath, 1963). These characters were then carefully studied and their characteristic expression or dimensions recorded, males and females separately. Whenever possible, five of each sex (selected at random) were used. This figure represented over 30% of the sample in hand in 75% of the species studied. In the present study 146 characters were used, comprising 52 asexual characters, 52 female charters and 42 male characters. The distribution of these characters over the animal was as follows: 14 head characters, 45 thoracic characters and 87 abdominal characters. Of these, 90 are descriptive, 16 metric, 20 ratios, and 20 meristic. A histogram of these characters and the number thereof applicable to Ectopsocus and Peripsocus is provided in Fig. 1; the species, their code numbers, and the number of individuals used in this study are listed in Table 1. A description of characters in some detail can be found in the manuscript of a thesis by the junior author submitted for the degree of Ph.D. at the University of Hong Kong. Analyses of the distribution of the number of states for the various types of