Michael A. Wall

The new stilt bug genus Bajacanthus, n. gen., and new species B. immaculatus, n. sp. are described from the Vizcaino Peninsula in Baja California Sur, Mexico. The berytid was discovered on the recently described endemic plant, Bajacalia moranii B. L. Turner (Asteraceae). A diagnosis, description, digital images of the adult male and female, the male genitalia capsule, and parameres are provided to facilitate recognition. A discussion of relationships is given and a revised key to the genera of the tribe Hoplinini (Gampsocorinae) is provided.

The Australian members of the emesine tribe Ploiaiolini (Hemiptera: Heteroptera: Reduviidae) are revised. A key, as well as diagnoses and figures, are presented for all 16 Australian species. Seven new species are described. Four species previously not recorded from Australia are included in the continent’s fauna. Emesopsis is expanded to include species in which the basal cell of the forewing is absent.

International audienceHyperaccumulator plants mobilize large amounts of certain elements from the soil into their tissues. Those elements then may be transferred to other organisms in those communities. Using a humid tropical forest site in New Caledonia, we tested whether epiphytes (mosses and liverworts) growing on Ni hyperaccumulator hosts contained greater levels of Ni (and seven other metals) than those growing on non-hyperaccumulator hosts. We selected two Ni hyperaccumulator species, Psychotria douarrei and Hybanthus austrocaledonicus, pairing individuals of each species with similar-sized non-hyperaccumulators and collecting epiphytes from each for elemental analysis. Samples of epiphytes and host plant leaves were analyzed for concentrations of eight metals (Co, Cr, Fe, Mg, Mn, Ni, Pb, and Zn). Two-way ANOVA was used to assess the influence of host type (hyperaccumulator or non-hyperaccumulator), epiphyte group, and the interaction term. Leaves of both Ni hyperaccumulator species had greater Ni concentrations than the paired non-hyperaccumulator species, but leaf concentrations of other metals (Co, Cr, Fe, Pb, and Zn) were higher as well in one or both cases. The strongest influence on epiphyte elemental composition was found to be the host type factor for Ni. Epiphytes collected from hyperaccumulator hosts had significantly greater Ni concentrations than those collected from non-hyperaccumulator hosts. Epiphyte Ni concentrations often exceeded the threshold used to define Ni hyperaccumulation (1000 µg/g), showing that some epiphytes (in most cases those growing on Ni hyperaccumulators) also hyperaccumulate Ni. Six of the epiphytes we analyzed, four liverworts (Frullania ramuligera, Schistochila sp., Morphotype #1 and Morphotype #13) and two mosses (Calyptothecium sp. and Aerobryopsis wallichii), had at least one specimen containing more than 1000 µg Ni/g and hence qualify as Ni hyperaccumulators. We conclude that Ni could move from Ni hyperaccumulator hosts to their epiphytes, either from leachates/exudates from tissues or from accumulated external dust, thus potentially mobilizing Ni still further into the food webs of these humid tropical forests

Hyperaccumulated elements such as Ni may defend plants against some natural enemies whereas other enemies may circumvent this defense. The Ni hyperaccumulator Berkheya coddii Roessler (Asteraceae) is a host plant species for Chrysolina clathrata (Clark), which suffers no apparent harm by consuming its leaf tissue. Beetle specimens collected from B. coddii had a whole body Ni concentration of 260 μg/g dry weight, despite consuming leaf material containing 15 100 μg Ni/g. Two experiments were conducted with adults of this beetle species: a no‐choice experiment and a choice experiment. In the no‐choice experiment we offered beetles foliage of one of four species of Berkheya: B. coddii, B. rehmannii Thell. var. rogersiana Thell., B. echinacea (Harv.) O. Hoffm. ex Burtt Davey, and B. insignis (Harv.) Thell. The two former species are Ni hyperaccumulators (defined as having leaf Ni concentration > 1 000 μg/g) whereas the latter have low Ni levels (< 200 μg/g) in their leaves. Masses of beetles were monitored for 6 days. Choice experiments used growing stem tips from the same Berkheya species, placed into Petri dishes with five Chrysolina beetles in each, and the amount of feeding damage caused on each of the four species was recorded. Beetles in the no‐choice experiment gained mass when offered B. coddii, maintained mass on leaves of the other Ni hyperaccumulator (B. rehmannii var. rogersiana), and lost mass when offered non‐hyperaccumulator leaves. In the choice test, beetles strongly preferred B. coddii to other Berkheya species. We conclude that C. clathrata may be host‐specific on B. coddii.

The Solomonius-group is a well-defined group of genera nested within the pentatomine tribe Halyini. The group contains 31 species, 20 of which are new to science. Species are classified into seven genera: Anchises Stål, Auxentius Horváth, Babylas Horváth, Brizica Walker, Elemana Distant, Epitoxicoris gen. nov., and Solomonius gen. nov. The genus Neoptolemus Horváth syn. nov. is synonymized with Brizica Walker. All species are described or redescribed and illustrated. Identification keys to all genera and species are provided. New species recognized are: Auxentius clandestinus sp. nov., Au. nigriculus sp. nov., Au. quasimodooides sp. nov., Au. vulgaris sp. nov. Au. zephyrius sp. nov., Brizica flyensis sp. nov., Br. sphaeroides sp. nov., Br. tubercularis sp. nov., Br. vandoesburgi sp. nov., Epitoxicoris allisonae sp. nov., Ep. trimaculatus sp. nov., Solomonius browni sp. nov., S. grossi sp. nov., S. laminaphallicus sp. nov., S. lestoni sp. nov., S. malaitaensis sp. nov., S. micrometallicus sp. nov., S. rideri sp. nov., S. schaeferi sp. nov., and S. viatorius sp. nov. Neoptolemus assimilis Horváth syn. nov. is synonymized with Br. proximus (Schouteden). The following new combinations are proposed within the Solomonius-group: Brizica exiguus (Distant) comb. nov., Br. humeralis (Horváth) comb. nov., Br. proximus (Schouteden) comb. nov., Solomonius foetidus (Signoret, 1861) comb. nov., S. ornatula (Distant) comb. nov., and S. viridula (Distant) comb. nov. A lectotype is designated for Solomonius foetidus (Signoret, 1861). One species is transferred out of the Solomonius-group of genera, resulting in a new combination, Baracellus distinctus (Schoutedon) comb. nov.

Nymphs of Stenoscepa sp. feed on leaves of the Ni hyperaccumulator Berkheya coddii at serpentine sites in Mpumalanga Province, South Africa. These sites contain Ni hyperaccumulators, Ni accumulators, and plants with Ni concentrations in the normal range. We conducted studies to: (i) determine the whole‐body metal concentration of nymphs (including those starved to empty their guts); (ii) compare Stenoscepa sp. nymphs against other grasshoppers in the same habitat for whole‐body metal concentrations; and (iii) compare the suitability of Ni hyperaccumulator and Ni accumulator plants as food sources for Stenoscepa sp. and other grasshoppers. Stenoscepa nymphs had extremely high whole‐body Ni concentrations (3 500 μg Ni/g). This was partly due to food in the gut, as starved insects contained less Ni (950 μg Ni/g). Stenoscepa nymphs survived significantly better than other grasshoppers collected from either a serpentine or a non‐serpentine site when offered high‐Ni plants as food. In a host preference test among four Berkheya species (two Ni hyperaccumulators and two Ni accumulators), Stenoscepa sp. preferred leaves of the Ni hyperaccumulator species. A preference experiment using leaves of three Senecio species (of which one species, Senecio coronatus, was represented by both a Ni hyperaccumulator and a Ni accumulator population) showed that Stenoscepa sp. preferred Ni accumulator Senecio coronatus leaves to all other choices. We conclude that Stenoscepa sp. is extremely Ni‐tolerant. Stenoscepa sp. nymphs prefer leaves of hyperaccumulator Berkheya species, but elevated Ni concentration alone does not determine their food preference. We suggest that the extremely high whole‐body Ni concentration of Stenoscepa nymphs may affect food web relationships in these serpentine communities.