Nesophrosyne broussaisiai

Bennett, Gordon M & O’Grady, Patrick M, 2011, Review of the native Hawaiian leafhopper genus Nesophrosyne (Hemiptera: Cicadellidae: Deltocephalinae) with description of eight new species associated with Broussaisia arguta (Hydrangeaceae), Zootaxa 2805, pp. 1-25 : 15-16

broussaisiai species subgroup

( Figs. 7 a–c & 8a–g)

Diagnosis. Dark species with conspicuous, highly variable pale coloration on clavus, ranging from entirely pale to a central oval saddle mark anteriorally flanked by pale blotches. Pronotum with posterior half pale. Pygofer with apex at 3/4 height from base; without basal lobe; dorsal edge depressed. Aedeagus with arms widening at mid length, showing an angular bend; apical processes absent in N. kaupoi . Endemic to Maui.

Description. Dorsum: Dark species with conspicuous and variable pale coloration on clavus. Crown predominately black with variable central pale mark at apex and a thin pale line along posterior margin. Pronotum dark with posterior pale band up to 1/2 width. Mesonotum dark. Scutellum pale. Clavus with saddle mark ranging in pale pigmentation; darkest forms with only a central round saddle mark, usually anteriorally flanked by lateral pale marks variable in size and color; palest forms with clavus appearing entirely pale with posterior angles dark.

Venter: Pleurites largely pale with variable central dark patches. Legs almost entirely pale; hind tibiae dark along anteroventral edge.

Genitalia: Pygofer apex bluntly rounded and turned slightly dorsad, rising 3/4 height from base; without basal lobe; posterior-dorsal edge depressed from slight to completely concave; dorsal edge flat, tapering towards anterior end; 13–15 macrosete. Aedeagus with arms widening at mid-length, showing an angular bend in ventral view; apical processes absent in N. kaupoi . Style large; posterior hooks comparatively thick; preapical lobe, sloping towards anterior end, rest of medial lobe rounded; posterior arm towards connective curving mesad, ‘s’ like. Connective anterior ends or arms curving, slightly hooked laterad.

Distribution. USA: Hawaiian Islands, Maui, 910m – 2080m, wet forest ( Fig. 3 )

Etymology. This species subgroup is named after the Broussaisia host plant genus.

Discussion. We describe three sibling species from Maui occurring on Broussaisia arguta . Genetic evidence demonstrates unique, reciprocally monophyletic evolutionary lineages with relatively high sequence divergence occurring on West Maui, East Maui Haleakalā windward face, and East Maui Haleakalā leeward face (Kaupo Gap). COII percent sequence divergence for these geographic ranges are as follows (Table 1): Haleakalā windward face – Haleakalā leeward face = 11.24%; Haleakalā windward face – West Maui = 4.22%; and, Haleakalā leeward – West Maui = 10.57%.

Morphologically, these species can be difficult to distinguish, but some external characteristics combined with geographic information are adequate to separate them. In general, West Maui represents a darker form than the both East Maui species, overlapping with N. ogradyi variants. N. kaupoi overlaps in color with the paler variants of N. ogradyi . Nesophrosyne kaupoi occurs at higher elevation (~ 2080m) than the other described species (910m – 1220m), which corresponds to the upper elevation of B. arguta .

The geographic structuring of these species provides unique insight into the potential evolutionary mechanisms that may contribute to the diversification of the genus. Haleakalā leeward, due to its inhospitable geographic divide across Haleakalā crater, high elevation, or differences in precipitation (or a confluence of all), may contribute to the genetic isolation and speciation of Nesophrosyne in this range. The distance, precipitation change and elevation change going from West Maui to East Maui are sufficient to maintain isolation between these species.

Figures

FIGURE 3. Partitioned Maximum Likelihood phylogeny of Nesophrosyne (Hemiptera: Cicadellidae) species reconstructed in RAxML-VI-HPC v 7.2.5 under a GTR + I + Γ likelihood model with 100 bootstrap partitions. Gene partitions are according to the mitochondrial genome (COII, 16 s) and nuclear genome (H 3, Wingless). Subsections A & B highlight species relationships of newly described species occurring on the host plant Broussaisia arguta. A) Silhouette of full Maximum Likelihood phylogeny results. B) Nesophrosyne heopoko’s associated with other species on Kaua’i. C) Relationships of the species within the kanawao species group on Maui and Hawai’i. The numbers above branches are bootstrap support values.

FIGURE 7. Dorsal habitus of the species comprising the kanawao species group: A. N. broussaisiai, B. N. ogradyi, C. N. kaupoi, D. N. kanawao, and E. N. aakokohaikea.