Higher‐level phylogeny of longhorn beetles (Coleoptera: Chrysomeloidea) inferred from mitochondrial genomes

Cerambycidae (longhorn beetles) and related families in the superfamily Chrysomeloidea are important components of forest ecosystems and play a key role in nutrient cycling and pollination. Using full mitochondrial genomes and dense taxon sampling, the phylogeny of Chrysomeloidea with a focus on Cerambycidae and allied families was explored. We used 151 mitochondrial genomes (75 newly sequenced) covering all families and 29 subfamilies of Chrysomeloidea. Our results reveal that (i) Chrysomelidae (leaf beetles) are sister to all other chrysomeloid families; (ii) Cerambycidae sensu stricto (s. s.) is polyphyletic due to the inclusion of other families that split Cerambycidae into a ‘lamiine’ clade comprising Lepturinae sensu lato (s. l.) + (Lamiinae + Spondylidinae) and a ‘cerambycine’ clade comprising Dorcasominae + (Cerambycinae + Prioninae s. l.); (iii) the subfamilies within the two clades of Cerambycidae s. s. were monophyletic, except for the placement of Necydalinae nested in Lepturinae, and the placement of Parandrinae within Prioninae (now considered as tribes Necydalini and Parandrini, respectively); (iv) smaller families were grouped into two major clades: one composed of Disteniidae+Vesperidae and the other composed of Orsodacnidae + (Megalopodidae + Oxypeltidae); (v) relationships among the four major clades were poorly supported but were resolved as ((cerambycines + (Disteniidae + Vesperidae) + Orsodacnidae + (Megalopodidae + Oxypeltidae)) + lamiines. Divergence time analyses estimated that Chrysomeloidea originated ca. 154.1 Mya during the late Jurassic, and most subfamilies of Cerambycidae originated much earlier than subfamilies of Chrysomelidae. The diversification of families within Chrysomeloidea was largely coincident with the radiation of angiosperms during the Early Cretaceous.     

Phylogenetic significance of the ventral nerve cord in the Chrysomeloidea (coleptera: Phytophaga)

Abstract The ventral nerve cord of adult Chrysomeloidea exhibits variation in the degree of fusion of the meso-and metathoracic ganglia. similar variation occurs also in the ganglia ofthe abdominal chain, and in the single or double connectives between them. In adult Chrysomeloidea (and Curculionoidea) there never seem to be more than five separate abdominalganglia, the first two being more or less fused to the metathoracic ganglion and the lasttwo more or lessconnate; the supposed primitive condition is retained in some Cerambycidae. Trends toward the fusion of aditional abdominal ganglia appear in several differentlines in Chrysomelidae (and in Cerambycidae), and in more than one line a conditiones is reached in which only the ganglion in the third abdominal segmetn remains free. Structures possibly representing 'perisynmpathetic organs' have been observed in a few of the seventy-eight European and Indian species studied. systematic and phylogenetic conclusions are drawwn.     

The adipokinetic hormone family in Chrysomeloidea: structural and functional considerations

The presented work is a hybrid of an overview and an original research paper on peptides belonging to the adipokinetic hormone (AKH) family that are present in the corpora cardiaca of Chrysomeloidea. First, we introduce the AKH/red pigment-concentrating hormone (RPCH) peptide family. Second, we collate the available primary sequence data on AKH peptides in Cerambycidae and Chrysomelidae, and we present new sequencing data (from previously unstudied species) obtained by liquid-chromatography coupled with ion trap electrospray ionisation mass spectrometry. Our expanded data set encompasses the primary structure of AKHs from seven species of Cerambycidae and three species of Chrysomelidae. All of these species synthesise the octapeptide code-named Peram-CAH-I (pGlu-Val-Asn-Phe-Ser-Pro-Asn-Trp amide). Whereas this is the sole AKH peptide in Cerambycidae, Chrysomelidae demonstrate a probable event of AKH gene duplication, thereby giving rise to an additional AKH. This second AKH peptide may be either Emppe-AKH (pGlu-Val-Asn-Phe-Thr-Pro-Asn-Trp amide) or Peram-CAH-II (pGlu-Leu-Thr-Phe-Thr-Pro-Asn-Trp amide). The peptide distribution and structural data suggest that both families are closely related and that Peram-CAH-I is the ancestral peptide. We hypothesise on the molecular evolution of Emppe-AKH and Peram-CAH-II from the ancestral peptide due to nonsynonymous missense single nucleotide polymorphism in the nucleotide coding sequence of prepro-AKH. Finally, we review the biological significance of the AKH peptides as hyperprolinaemic hormones in Chrysomeloidea, i.e. they cause an increase in the circulating concentration of proline. The mobilisation of proline has been demonstrated during flight in both cerambycid and chrysomelid beetles.     

Untersuchungen zur Feinstruktur der Augen von Bockkäfern (Coleoptera,Cerambycidae)

Zusammenfassung Es wurden die Augen von 55 Cerambycidae-Arten aus 6 Unterfamilien elektronenmikroskopisch untersucht. Jedes Auge setzt sich aus aconen Ommatidien mit je einer bikonvexen Cornea-Linse, 4 SemperZellen, 8 Retinula-, 2 Haupt-, sowie einer größeren und unterschiedlichen Anzahl von Nebenpigmentzellen zusammen.Die verschiedenen Anordnungen der einzelnen Rhabdomere in den in der Regel offenen Rhabdomen lassen sich in 2 Grundmustern zusammenfassen, wobei im Falle von Grundmuster 1 die zentralen Rhabdomere R 7/8 von den peripheren R 1–6 räumlich vollkommen isoliert sind. Grundmuster 2 liegt dann vor, wenn R 7/8 über einen strukturellen Kontakt mit R 1 und R 4 mit dem peripheren Rhabdomeren-System verbunden sind. Innerhalb jedes Grundmusters treten verschiedene Rhabdomeren-Formen auf, die sich insbesondere aus unterschiedlichen Mikrovilli-Streichrichtungen von R 7 und R 8 ergeben. Außerdem kommt es innerhalb einiger Taxa zu partiell fusionierten, bei einer einzigen Art sogar zu vollkommen fusionierten Rhabdomen. Die Ableitung von offenen Rhabdomen mit entsprechender Grundmuster-Zugehörigkeit gelingt in jedem Fall über eine eindeutige Homologisierbarkeit der beteiligten Retinulazellen.Die wichtige Frage nach der Taxon-Spezifität der rhabdomerialen Muster läßt nach ihrer Beantwortung Aussagen über den Wert ultrastruktureller Muster für phylogenetische Argumentationen zu. Die bei den Cerambycidae ausgeprägte ungleichförmige Verteilung von Rhabdom-Mustern innerhalb niederer, näher verwandter Taxa zeigt (im Vergleich mit den jeweils außerordentlich ähnlichen Rhabdomen der Chrysomelidae, Wachmann, 1977, deren gute Unterfamilien-Spezifität weitere Stützung erfährt) das Auftreten von Konvergenzen. Diese lassen sich jedoch nur am System selbst nachweisen. Somit zeigt es sich, daß die Muster offener Rhabdome nur als mehr oder weniger gute zusätzliche Indizien für die Monophylie von Gruppen herangezogen werden können, die jedoch mit Hilfeanderer Merkmale aufgestellt worden sind. Trotz hochgradiger Übereinstimmungen sind Rhabdom-Merk-male für sich allein genommen nicht hinreichend geeignet, um monophyletische Gruppen auszugliedern.Die vergleichend morphologischen Untersuchungen bilden eine gute Grundlage für funktionelle Interpretationen der verschiedenen Rhabdome. Ungelöst bleibt jedoch die Frage, ob den Sehzellen derart unterschiedlich konstruierter Rhabdome gleiche oder verschiedene neurale Verschaltungsstrategien im Bereich von Lamina und Medulla zugrunde liegen.

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Comparative morphological investigations on the ultrastructure of long-horned beetles (Coleoptera, Cerambycidae)

Summary The eyes in 55 species of 8 subfamilies of long-horned beetles (Cerambycidae) have been examined ultrastructurally. An eye consists of acone ommatidia of which each is assembled by a bi-convex corneal lens, 4 Semper-cells, 8 retinula cells, 2 primary pigment cells, and of a larger and variable number of secondary pigment cells.The differently arranged rhabdomeres of the — as a rule — open rhabdoms can be summed up to two basic patterns: In the case of the basic pattern 1 the central rhabdomeres R 7/8 are completely isolated from the peripheral rhabdomeres R 1–6. As to the basic pattern 2 the central rhabdomeres R 7/8 are structurally attached to the peripheral rhabdomere arrangement through R 1 and R 4. Due to different directions of the microvilli in R 7 and R 8 there occur several rhabdomeral shapes. Furthermore, within some taxa partially fused rhabdoms are present; in one species the fusion is even complete. Nevertheless, a derivation from an open rhabdom with reference to one of the basic patterns is always possible due to a clear homologous comparison of the anticipating retinula cells.The successfully answered question upon a taxon-specifity of the basic patterns and the rhabdomeral shape allows statements as to the value of these ultrastructural patterns for a phylogenetic argumentation. In Cerambycidae the distinct and not uniform arrangement of these patterns and shapes within lower, closer related taxa represents the occurrence of convergencies (as compared to the extraordinarily similar rhabdoms in Chrysomelidae, Wachmann, 1977, which receive in this paper a further support as to their subfamiliar specification). However, these convergencies are demonstrable through the phylogenetic system only. Thus, patterns of open rhabdoms can only be used as more or less additional indices on a monophyly of groups which already has been proved by means of other characteristics. In spite of an extreme conformity within different taxa rhabdomeral characteristics solely are not appropriate enough in order to separate monophyletic groups.The ultrastructural investigations give a good basis as to the interpretation of the function of the different rhabdoms. However, the question remains not answered whether there exist equal or unequal strategies of circuits within the lamina and medulla.

     

Chromosome numbers of Coleoptera from Argentina

A list is presented containing data on chromosome numbers and sex determining mechanisms of 90 species of Argentina beetles, belonging to the families Staphylinidae (2 spp.), Meloidae (3 spp.), Elateridae (1 sp.), Coccinellidae (5 spp.), Tenebrionidae (11 spp.), Scarabaeidae (30 spp.), Cerambycidae (3 spp.), Chrysomelidae (27 spp.), Curculionidae (7 spp.) and Lampyridae (1 sp.), Asphaera t-album (Chrysomelidae) had n=10+X+6y; in Epicauta atomaria (Meloidae) individuals with 2 n=22, 21 and 20 were found.This work was supported by grants of National Research Council of Argentina (CONICET) and SUBSYT.     

Genital feelers: the putative role of parameres and aedeagal sensilla in Coleoptera Phytophaga (Insecta)

The male copulatory organ (aedeagus) of the Curculionoidea and the Chrysomeloidea is originally composed of a median lobe and a tegmen with basal struts and distal parameres. Within the Phytophaga (=Pseudotetramera), the parameres have been reduced several times. Comparison of different types of parameres, median lobes, aedeagi lacking parameres, and investigation of dissected pairs in copula revealed that (1) parameres do not provide mechanical coupling, (2) mechanical footing is provided by the endophallus, (3) median lobes of Phytophaga bear different kinds of sensilla. Mechanical and behavioural interaction between male and female copulatory organs were studied morphologically and by observation of live, copulating pairs. For the first time, copulation of a Sagrinae-species (Chrysomelidae: Sagrinae: Mecynodera coxalgica) was investigated in detail.     

Cell Adhesion and Fusion Induced by Insemination in Zona-Free Hamster Eggs: Electrophysiological Monitoring of the Fusion Process

Cell adhesion and fusion were found to occur in zona-free hamster eggs placed in contact and then inseminated. A cytoplasmic fusion occurred in 7% of paired eggs mainly between 10 and 50 min after insemination. All other eggs that failed to fuse adhered tightly to one another within about 1 hr. Electrophysiological monitoring of the fusion process revealed that an electrical coupling (EC) suddenly appears between apposed eggs and completed within 2–15 min as the first step of cell fusion. Periodic hyperpolarizing responses (HRs), which have been found previously in fertilized hamster eggs to reflect a periodic increase in cytoplasmic Ca²⁺ ions, become gradually synchronized and completely coincide in paired eggs 10–30 min after the establishment of EC. Thus the paired eggs become an electrically single cell as the second step. Then the boundary between the eggs breaks down, resulting in formation of a single, spherical egg in several minutes. On the other hand, most of adhered eggs showed neither EC nor synchronization of HRs. Some adhered eggs showed only a low efficiency EC.     

酯酶同工酶在鞘翅目昆虫分类中的应用简介

简要介绍了酯酶同工酶电泳技术在鞘翅目昆虫分类研究中的应用。包括叶甲科Chrysomelidae、天牛科Cerambycidae、小蠹科Scolytidae、瓢虫科Coccinelidae、豆象科Bruchidae、金龟子科Scarabaeidae、萤科Lampyridae和苔水龟虫科Hydraenidae等。     

Dialkyl-μ-ethylidene-μ-methylene-bis(pentamethylcyclopentadienyl)-dirhodium complexes: synthesis, spectra and decomposition reactions

The dialkyl-μ-ethylidene-μ-methylene-bis (pentamethylcyclopentadienyl)-dirhodium complexes [{(C₅Me₅)Rh}₂(μ-CH₂)(μ-CHMe) (R)₂] (4, P=Me; 5, Et; 6, n-Bu; 7, CH=CH₂; and 8, Z-CH=CHMe) have been prepared from RMgBr and [{(C₅Me₅)Rh}₂(μ-CH₂)(μ-CHMe)(X)₂] (2, X=Cl; 3, X=Br). Structures deduced from the NMR spectra show that the dialkyl complexes can exist in one trans and two cis forms. The decomposition of the dimethyl complex 4 is compared with that of the related di-μ-methylene complex; it reacts readily (30°C, MeCN solution) in the presence of one-electron oxidisers to give propene and methane and a little ethene and some butenes. Mass-spectrometric analysis of the ¹³C labelling in the organics originating from [{(C₅Me₅)Rh}₂(μ-CH₂)(μ-CHMe) (¹³CH₃)₂] shows that methane derives from the Rh---Me, ethene half from the ethylidene and half from coupling of Rh-methyl and a bridging methylene, while the propene arises almost entirely from the ethylidene and a rhodium methyl. The butenes come from coupling of ethylidene, methylene and a Rh-methyl, but only quite small amounts are formed; thus C+C coupling is the major decomposition path for the μ-ethylidenes, in contrast to the di-μ-methylene complexes where C+C+C coupling predominates. The divinyl complex [{(C₅Me₅)Rh}₂(μ-CH₂)(μ-CHMe) (CH=CH₂)₂] also underwent internal C+C coupling on reaction with AgBF₄ in MeCN to give a mixture of the allyl and methylallyl cations [(C₅Me₅)Rh(η³-CH₂CHCHR)(MeCN)]⁺(10, R=H; 11, R=Me).     

C-bands on chromosomes of 32 beetle species (Coleoptera: Elateridae, Cantharidae, Oedemeridae, Cerambycidae, Anthicidae, Chrysomelidae, Attelabidae and Curculionidae)

C-banding patterns of 32 beetle species from the families Elateridae, Cantharidae, Oedemeridae, Cerambycidae, Anthicidae, Chrysomelidae, Attelabidae and Curculionidae were studied using the C-banding technique. Mitotic and meiotic chromosomes were previously described for 14 species. From among 18 species that had never been cytogenetically studied, we determined the diploid and haploid chromosome numbers and the sex determination system for 12 beetles. The karyotype for 6 species is not described because of a lack of mitotic and meiotic metaphases. Results confirm that most of the beetle species possess a small amount of heterochromatin and C-positive segments are weakly visible in pachytene stages and weakly or imperceptible in mitotic and meiotic metaphases. In some species with a large amount of heterochromatin, C-bands were observed in the centromeric region in all autosomes and the X chromosome. The Y chromosome does not show C-bands with the exception of Oedemera viridis in which it possesses a small band of heterochromatin.     

Early duplication and functional diversification of the opsin gene family in insects

Recent analysis of the complete mosquito Anopheles gambiae genome has revealed a far higher number of opsin genes than for either the Drosophila melanogaster genome or any other known insect. In particular, the analysis revealed an extraordinary opsin gene content expansion, whereby half are long wavelength-sensitive (LW) opsin gene duplicates. We analyzed this genomic data in relationship to other known insect opsins to estimate the relative timing of the LW opsin gene duplications and to identify "missing" paralogs in extant species. The inferred branching patterns of the LW opsin gene family phylogeny indicate at least one early gene duplication within insects before the emergence of the orders Orthoptera, Mantodea, Hymenoptera, Lepidoptera, and Diptera. These data predict the existence of one more LW opsin gene than is currently known from most insects. We tested this prediction by using a degenerate PCR strategy to screen the hymenopteran genome for novel LW opsin genes. We isolated two LW opsin gene sequences from each of five bee species, Bombus impatiens, B. terrestris, Diadasia afflicta, D. rinconis, and Osmia rufa, including 1.1 to 1.2 kb from a known (LW Rh1) and 1 kb from a new opsin gene (LW Rh2). Phylogenetic analysis suggests that the novel hymenopteran gene is orthologous to A. gambiae GPRop7, a gene that is apparently missing from D. melanogaster. Relative rate tests show that LW Rh2 is evolving at a slower rate than LW Rh1 and, therefore, may be a useful marker for higher-level hymenopteran systematics. Site-specific rate tests indicate the presence of several amino acid sites between LW Rh1 and LW Rh2 that have undergone shifts in selective constraints after duplication. These sites and others are discussed in relationship to putative structural and functional differences between the two genes.     

The timing of the electromyogram in the lateral myotomes of mackerel and saithe at different swimming speeds

Electromyogram (EMG) signals from two points at about 40% L and 65% L ( L = length) in the left latera1 muscle of mackerel ( Scomber scombrus L.) L = 28–33 cm a nd saithe ( Pollachius virens L.) L = 42–50 cm were recorded synchronously with films of steady straight swimming motions. In both species, the duration of EMG activity at both electrodes, remains a constant proportion of the tail cycle period Tat all the tail beat frequencies between 1–8 and 13 Hz. In mackerel and saithe respectively: onset of EMG activity at the front was 74% T and 77% T before the left-most tail blade position and fronl EMG-onset occurred 15% T and 18% T before rear onset. The duration of the EMG burst is longer at the front position (41% T and 47% T ) than at the rear (25% T and 27% T ), At all swimming speeds the wave of electrical activation of the muscle travelled between the two electrodes 25% L apart at a velocity between 1.5 and 1.6 L T ⁻¹. Frequencies of spikes within the burst of EMG activity rose from 30–40 Hz at 2 T s⁻¹ to 50–80 Hz at 8 T s⁻¹. In muscle at 40%L EMG-onset happens at phase 30° just after muscle strain at this point reaches its resting length while lengthening (360°). At 65% L EMG-onset occurs earlier in the strain cycle-350° just before the muscle reaches it resting length while lengthening (360°). This could represent within the length of the fish, a phase shift of up to 90° in the EMG-onset in relation to the muscle strain cycle. These timings are discussed in relation to optimized work output and a single instant of maximum bending moment all along the left side of the body.     

The effect of temperature and fish size on growth and feed efficiency ratio of juvenile spotted wolffish Anarhichas minor

The growth properties of juvenile spotted wolffish Anarhichas minor reared at 4, 6, 8 and 12° C, and a group reared under 'temperature steps', (T‐step) i.e . with temperature reduced successively from 12 to 9 and 6° C were investigated. Growth rate and feed efficiency ration was significantly influenced by temperature and fish size. Overall growth rate was highest at 6° C (0·68% day⁻¹) and lowest at 12° C (0·48% day⁻¹), while the 4 and 8° C, and the T‐step groups had similar overall growth rates, i.e . 0·59, 0·62 and 0·51% day⁻¹ respectively. Optimal temperature for growth ( T _{opt G} ) and feed efficiency ratio (T_{opt FCE}) decreased as fish size increased, indicating an ontogenetic reduction in T _{opt G} and T _{opt FCE}. The results suggest a T _{opt G} of juvenile spotted wolffish in the size range 135–380 g, dropping from 7·9° C for 130–135 g to 6·6° C for 360–380 g juveniles. The T _{opt FCE} dropped from 7·4° C for 120–150 g to 6·5° C for 300–380 g juveniles. A wider parabolic regression curve between growth, feed efficiency ratio and temperature as fish size increased, may indicate increased temperature tolerance with size. Individual growth rates varied greatly at all time periods within the experimental temperatures, but at the same time significant size rank correlations were maintained and this may indicate stable size hierarchies in juvenile spotted wolffish.     

The amino-terminus of phytochrome A contains two distinct functional domains

The N-terminus of phytochrome A is important for the structural integrity and biological activity of the photoreceptor. Mutational analysis of the N-terminus by two different strategies created two distinct photoreceptors, one inactive and the other hyperactive when expressed in transgenic tobacco, suggesting that this region has multiple functional domains. To identify critical residues within this N-terminal region, a series of smaller deletions of oat phytochrome A were created, designated NB (Δ49–62), NC (Δ6–47), ND (Δ7–21), NE (Δ2–5), and NF (Δ6–12), and compared with a previously characterized deletion mutant NA (Δ7–69) and full-length oat phytochrome A. Using photochemical properties as a measure of chromoprotein structure, it was found that the region between residues 13 and 62 was important for the spectral integrity of the photoreceptor. These deletion mutants were also biologically inactive when expressed in both mature tobacco plants and seedlings grown under continuous far-red or red light. In contrast, deletion of the serine-rich region between residues 6 and 12 did not alter the photochemical properties but did produce a hyperactive photoreceptor, indicating this region may be involved in down-regulating phytochrome A activity. The data show that the N-terminus of phytochrome A contains two functional domains, one necessary for conformational stability and biological activity (residues 13–62), and the other involved in attenuating phytochrome responses (residues 6–12).     

Ligand-mediated metal-metal interactions in (ν:ν-fulvalene) bis (dicarbonylcobalt) and rhodium complexes

Gas phase photoelectron spectroscopy (PES) is used to investigate the bonding and electronic structure in (fv) [M(CO)₂]₂ (fv = fulvalene, η⁵:η⁵-C₁₀H₈²⁻; M = Co, Rh). The results for these bimetallic complexes are also compared to those for the analogous monometallic complexes CpM(CO)₂ (Cp = η⁵−C₅H₅⁻; M = Co, Rh) which have been reported previously. The low valence ionization patterns observed for CpCo(CO)₂ and (fv)[Co(CO)₂]₂ are very similar, indicating that there is little electronic interaction between the two metals of the dicobalt complex. The spectrum of (fv)[Rh(CO)₂]₂ also is very similar to the spectrum of CpRh(CO)₂, except that the first metal ionizations in the bimetallic rhodium compound show a significant splitting (0.45 eV). This splitting is due to electronic interaction between the two metal centers which occurs via communication through the fulvalene π system. The differences in electronic structure are compared to the differences in electrochemical behavior of the Co and Rh fulvalene complexes.     

Effects of met-enkephalin on electrical coupling between identified neurons in the pulmonate snails,Helix and Lymnaea

1. The effects of met-enkephalin on electrical coupling between molluscan neurons have been investigated using the isolated brains of Helix pomatia and Lymnaea stagnalis.2. In the presence of both serotonin and met-enkephalin, non-rectifying electrical coupling is strongly facilitated between identified respiratory neurons in Helix, whilst coupling between putative, serotonin-containing, ciliomotoneurons in Lymnaea is facilitated by met-enkephalin alone.3. Facilitation of coupling by met-enkephalin is weaker in the strongly coupled neurons, VDl/RPaD2 of Lymnaea.4. These data suggest that met-enkephalin can modulate different groups of electrically coupled cells and may be involved in coordination of motor patterns.     

STAGING OF NEWT BLASTULA EMBRYOS AND FIRST APPEARANCE OF PRIMARY MESODERMAL COMPETENCE

Using the swimbladder of the crusian carp ( Carrasius auratus ) as an inductor, the first appearance of mesodermal competence in the presumptive ectoderm of the newt ( Triturus pyrrhogaster ) blastula was investigated. The time course of embryonic development before the gastrula stage was determined by counting the number of surface cells on a 0.25 mm line at the animal pole. Pregastrula embryos with 2–3, 4–5, 6–7 and 7–8 cells roughly correspond to those at 14, 14–12, 8–6 and 4–0 hr before the beginning of gastrulation. Using presumptive ectoderm of the early gastrula stage, 15 min was found to be the minimum time of contact necessary for the realization of induction. The reactivity of the presumptive ectoderm from pregastrula embryos was tested by 30 min contact. Presumptive ectoderm up to the 4–5 cell stage did not react to the inductor. It may become competent within the next 4–8 hr, since the ectoderm from embryos in the 6–7 cell stage was reactive.     

Foot joint coupling variability differences between habitual rearfoot and forefoot runners prior to and following an exhaustive run

As joint coupling variability has been associated with running-related lower extremity injury, the purpose of this study was to identify how variability within the foot may be different between forefoot (FFS) and rearfoot strike (RFS) runners. Identifying typical variability in uninjured runners may contribute to understanding of ideal coordination associated with running foot strike patterns.Fifteen FFS and 15 RFS runners performed a maximal-effort 5 km treadmill run. A 7-segment foot model identified 6 functional articulations (rearfoot, medial and lateral midfoot and forefoot, and 1st metatarsophalangeal) for analysis. Beginning and end of the run motion capture data were analyzed. Vector coding was used to calculate 6 joint couples. Standard deviations of the coupling angles were used to identify variability within subphases of stance (loading, mid-stance, terminal, and pre-swing). Mixed between-within subjects ANOVAs compared differences between the foot strikes, pre and post run.Increased variability was identified within medial foot coupling for FFS and within lateral foot coupling for RFS during loading and mid-stance. The exhaustive run increased variability during mid-stance for both groups.Interpretation. Joint coupling variability profiles for FFS and RFS runners suggest different foot regions have varying coordination needs which should be considered when comparing the strike patterns.