Figure Legends

Figure 1

Top: Three pattern themes occupied by six Heliconius species in Corcovado Park, Pacific lowlands, Costa Rica. ESS (pupal mating) clade, (LEFT COL, FROM TOP) hecalesia, hewitsoni, erato (a-c-e) and MCS clade, (RIGHT COL, FROM TOP) hecale, pachinus, melpomene (b-d-f).

Middle: Rainforest understory Müllerian partners in the Atlantic forests of Costa Rica: H. sapho (g) and H. cydno (h).

Bottom: Red (di-hydro-xanthommatin) gene from H. melpomene (f) expressed as shutter marker in H. cydno galanthus (i) and H. pachinus (j). See text.

Hybrid derived from cydno galanthus x melpomene rosina completely shuttered and red DFW cydno window (a) is opposed on ventral HW by white (type I) scales (b). This D/V "shutter off" switch is derived from melpomene. See text.

Shutter of ventral FW distal window (c) converted to brown (type III scales) in this F1 pachinus x melpomene. Ventral "shutter on" of cydno group is epistatic to "shutter off" of melpomene (compare to b above). See text.

a. Spontaneously produced VFW to VHW homeosis transfers several patches of FW scale patches to homologous areas of HW demonstrating cell autonomous nature of pattern control. (from Gilbert in prep)

b. X-irradiation of egg 72 hrs after oviposition produced this clone of white scales which originates at the base of the DFW and terminates precisely at the window-wall boundary as highlighted by red shutter in this individual from a cydno x melpomene hybrid population. It is not precisely known how long after fertilization treatment was given (terminal eggs in the oviduct can be held several days post fertilization before being laid) and genetic damage might slow development of a mutant clone. Nevertheless, one can conclude that the FW window/wall boundary had to have been established before this clone, which occupies approx. 6% of the FW, could spread the full length of the wing. (from Gilbert in prep).

c.- f. Examples of clones of contrasting scale pigmentation and morpho-type resulting from somatic crossing-over induced by X-ray. In these cases recessive alleles or repressed loci were expressed as homozygous scale phenotypes on the wings of heterozogous individuals in pattern fields otherwise expressing dominant or epistatic phenotypes. Note that such clones become progressively larger according to how earlier in development embryos were irradiated, demonstrating lineage autonomy in cells which give rise to wing scales. Clones comparable to that of (c) in size only occur if early stage larvae are irradiated. Irradiations of pupae result in single scale changes.

c. scales homozygous for lack of shutter (patch of yellow, type I scales) on DHW window region otherwise expressing type II scales (melanic)

d. patch of homozygous red scales interrupt VHW brown line in individual heterozygous for brown/red ommatin in type III scales

e. patch of homozygous black scales (type II) within DFW shutter composed of red (type III ) scales on butterfly heterozygous for shutter color locus

f. clone of homozygous yellow scales (type I) expressed against field of white (type I) within FW window heterozygous for 3-hydroxy-L-kynurenine gene.

Upper Left: Sample of novel patterns arising in synthetic hybrid zones involving Costa Rican melpomene rosina (a), cydno galanthus (b), and pachinus (c). Individuals (d) and (e) share melpomene window and shutter settings in FW distal window but lack red. Individuals (f) and (h) share hybrid shutters (red) but differ in window size. pachinus proximal FW/HW shutter affects (d), (f), (g), and (i) and (l). See text.

Upper Right: Segregation of FW and HW shutters in hybrids of H. pachinus and H. cydno galanthus. Parents (top) were offspring of pure pachinus backcrossed to cydno x pachinus F1. These patterns are among the many that also appear in F2 broods in nature in central Costa Rica.

Lower Left: Independence of shutters and windows in pseudo F2 of H. melpomene (a) x H. pachinus (d). (b) is interpreted as homozygous for melpomene FW shutter position and pachinus window. (c) is interpreted as near homozygous at 2-3 loci (?) for pachinus shutter position on pachinus window. Shutters are red in (b) and (c). See text.

Lower Center: One brood of a three way "hybrid zone" of cydno galanthus, pachinus, and melpomene rosina (all Costa Rica). Parents are a female F2 of cydno x pachinus showing shutter-free HW windows (a) and melpomene x cydno F1 (b). This 1983 brood demonstrated that the melpomene red marked the FW shutter, and suggested a clade-wide "toolbox" and hybrid origins for H. heurippa (resembles d) and H. cydno weymeri (distal FW like c). A specimen resembling (d) was taken in 1993 on the Rio Sarapiqui in Costa Rica and is deposited in the Museo Nacional of Costa Rica.

Lower Right: Backcross of melpomene x cydno to pure melpomene. FW window type I scale color segregates yellow-white approx. 1:1 as does HW shutter (of cydno origin). Note pattern of shuttering of proximal half of FW revealed by removal of red in that region (e.g., see a, c, i, k, etc.). This trait distinguishes form alithea from haenshii in polymorphic cydno in W. Ecuador. See Fig 7 and text.

Two VHW phenotypes which appear in synthetic hybrid zone of cydno x pachinus. Unshuttered HW window bordered by brown line (a) and heterozygote for cydno HW shutter, lacking brown line (b). Ventral pattern of wildtype cydno galanthus (c) and pachinus (d). Compare (e) below with cydno. See text.

(e) This Costa Rican specimen of H. cydno was described as a new species by Schaus (1913). It represents a phenotype which appears in the F2 of cydno x pachinus. The HW window area, completely "shuttered" is highlighted by brown scales. Note lack of D/V match on proximal boundary of FW shutter, a common feature of hybrids. See text.

(f) This synthetic hybrid zone specimen is homozygous for the brown shutter phenotype and is probably the same genotype as (e).

(g) Heterozygote for "forceps" shutter which in cydno converts brown shuttered oval window into an arch matching opposite brown line, thus creating a forceps motif.

Schematic diagram indicates the sequence of layers revealed by hybridization and illustrated by the specimens in this figure. Proceeding from (a) to (c): unshuttered window (a); heterozygous for cydno HW shutter (b); homozygous for same shutter (no photo); heterozygous for brown shutter color (no photo); homozygous for same locus (e and f); heterozygous for "forceps" shutter (g); homozygous for "forceps" shutter (c).

Diagrams of windows and shutters of cydno (left) and pachinus (right) related to ventral pattern of cydno x pachinus F1 wing showing many of the pattern elements discussed in text: proximal boundary of FW distal window (a), proximal boundary of FW hybrid shutter (b), the FW distal shutter (c), the distal boundary of that shutter (d), window wall boundary (e), pachinus proximal shutter on FW (f), the homologous shutter on HW (f'), position of pachinus yellow bar, shuttered, is seen as a zone of higher reflectance and the brown line (h). Note that the "forceps" shutter of cydno is not perceptible as it is overlapped by both cydno HW (i) and pachinus HW (j) shutters. HW window-wall distal boundary is (g).

Top: Expression of some H. melpomene pattern genes in H. cydno background.
a. H. melpomene-typical "dennis-ray" race from W. Amazonia.

b. H. cydno galanthus , Costa Rica; (m) shows ventral of this race.

c. H. melpomene rosina , Costa Rica; (l) shows ventral of this race.

d. Ventral view of backcross [(a x b) F1 x b] ; compare to ventral of pure galanthus (m).

g. "pseudo F2" derived from (b x c) shows melpomene yellow FW distal window with hybrid shutter on its distal half. Note that shuttering of cell region of proximal FW identical to that seen in this lab hybrid occurs in nature as a trait of cydno form haenshii (j).

e., f., and h. are also"pseudo F2" phenotypes derived from (b x c). Compare these with naturally occuring forms (i) and (k), H. cydno alithea, and (j), H. c. haenshii from W. Ecuador. See text

Lower Left: Mimicry of novel pattern in two steps. H. cydno races galanthus (a) and weymeri F . gustavi (b) produced intermediate F1 (c, d). F2 brood produces several novel patterns (e-k), including (g) which is a close mimic of a distasteful pericopid moth common on the Osa Peninsula of Costa Rica (Lower Right). See text.

Middle Right: One step mimicry. Crossing species H. cydno alithea (a) and H. ismenius (b) yields F1 phenotypes (c, d, e) which mimic Ecuadorian H. hecalesia (f, g). Males of F1 are fertile. See text.

Lower Right: Colobura dirce , called the "mosaic" appears to illustrate two modes of pattern determining mechanisms. See text.

A sample of novel patterns generated in synthetic hybrid zones involving several races each of H. cydno and H. melpomene. See text.

Annotated phylogeny of the sub-tribe Heliconiiti (Nymphalidae, Heliconiinae) showing Heliconius species and species-groups discussed in text. Higher-level relationships are based on Penz (1999), and species-level relationships for Heliconius follow Brower and Egan (1997) modified to include H. hecalesia within the ESS clade as proposed by Brown (1981). Taxa in bold are referenced in text. Asterisk indicates described species from cydno group suggested to arise from cydno x melpomene hybridization. MCS and ESS clades are described and discussed in text.

The biodiversity cycle for Heliconius. This diagram summarizes the sequence, of events and processes which constitute a positive feedback loop generating both wing pattern and species diversity in Heliconius. The unique thing about the Heliconius system, as proposed in this chapter, is the creation of novel wing pattern variants when genes of the MCS "tool box" recombine by introgression in hybrid zones (Step I). Steps II-VII: co-occurring evolutionary processes of migration, drift, and selection, summarized here as "shifting balance" (II), which filter among available variants, geographical differentiation in allopatry or parapatry (III) which refines the genomic correlates of a newly established pattern (IV) and later the evolution of reproductive isolation (VI) which completes the prerequisites for packing into an existing community (V-VII) have been previously proposed with the assumption that mutation alone (indicated by the dotted line) produces step I. Major innovations in courtship and mating (e.g.. pupal mating) or in behaviors such as larval host preference, or in habitat preferences promote the evolution of niche differences (IV) as well as reproductive isolation (VI) and lead to local saturation in coexisting species and mimicry rings. This local genetic diversity is stored in local communities (VII) from which individuals occasionally disperse into hybrid zones to mate with and mix genes with those of individuals whose source populations had experienced a different history (VIII and IX). Not shown are factors which constrain local diversity (relevant to II-IV and VI-VII) such as micro habitat and host plant diversity and predator-imposed selection for Müllerian convergence. While the packing of species and wing patterns is limited locally, diversity builds among areas so that the cycle described continues to increase the overall biodiversity of the genus both with respect to taxonomic as well as phenotypic diversification. Bold squares enclose the major products of the processes described, from novel patterns in hybrid zones to their ultimate output: genus-wide biodiversity. See text for further discussion.