Observations on the ecology and behaviour of the New Zealand giraffe weevil (<i>Lasiorhynchus barbicornis</i>)

Painting, Christina J.; Holwell, Gregory I.

doi:10.1080/03014223.2013.854816

Cited by 16 publications

(16 citation statements)

References 7 publications

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“…within the same tree) in relation to the amount of moisture, sap and fungi available (Cassidy et al, 2014). Patchiness in the quality of available host trees could drive developmental plasticity or variation in selection on rostrum size, particularly given the large number of tree species/ families utilized (Painting & Holwell, 2014b).…”

Section: Discussionmentioning

confidence: 99%

“…To do this, breeding experiments are required, conducted under different temperature regimes using representatives from different latitudes (Fairbairn, 2005;Hallsson & Bjorklund, 2012;Tsuchiya et al, 2012). Unfortunately, L. barbicornis have a long larval developmental time of at least 2 years (Painting & Holwell, 2014b), which makes these breeding experiments difficult.…”

Section: Discussionmentioning

confidence: 99%

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Weapon allometry varies with latitude in the New Zealand giraffe weevil

Painting

Buckley

Holwell

2014

J of Evolutionary Biology

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Animal body size commonly shows a relationship with latitude to the degree that this phenomenon is one of the few ‘rules’ discussed in evolutionary ecology: Bergmann's rule. Although exaggerated secondary sexual traits frequently exhibit interesting relationships with body size (allometries) and are expected to evolve rapidly in response to environmental variation, the way in which allometry might interact with latitude has not been addressed. We present data showing latitudinal variation in body size and weapon allometry for the New Zealand giraffe weevil (Lasiorhynchus barbicornis). Males display an extremely elongated rostrum used as a weapon during fights for access to females. Consistent with Bergmann's rule, mean body size increased with latitude. More interestingly, weapon allometry also varied with latitude, such that lower latitude populations exhibited steeper allometric slopes between weapon and body size. To our knowledge, this is the first study to document a latitudinal cline in weapon allometry and is therefore a novel contribution to the collective work on Bergmann's rule and secondary sexual trait variation.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Weapon allometry varies with latitude in the New Zealand giraffe weevil

Painting

Buckley

Holwell

2014

J of Evolutionary Biology

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“…Observations took place during summer in an area of native coastal broadleaf forest at Matuku Reserve (36° 51.92′S, 174° 28.32′E), west of Auckland City, New Zealand, known for its reliable and large giraffe weevil population (Painting and Holwell ). Aggregations of giraffe weevils were located on sick or dead standing karaka trees ( Corynocarpus laevigatus ), the most common host species at Matuku Reserve (Painting and Holwell ). For this study, when referring to the population we are referring to all of the weevils across the reserve.…”

Section: Methodsmentioning

confidence: 99%

“…New Zealand giraffe weevils ( Lasiorhynchus barbicornis , Coleoptera: Brentidae) present an exciting opportunity for investigating sexual selection in the wild. They are found in aggregations on trees during the day, where they mate and females lay their eggs (Meads ; Painting and Holwell ), making them easy to observe. Giraffe weevils are sexually dimorphic (Fig.…”

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confidence: 99%

Directional selection on body size but no apparent survival cost to being large in wild New Zealand giraffe weevils

et al. 2019

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When an individual's reproductive success relies on winning fights to secure mating opportunities, bearing larger weapons is advantageous. However, sexual selection can be extremely complex, and over an animal's life the opportunity to mate is influenced by numerous factors. We studied a wild population of giraffe weevils (Lasiorhynchus barbicornis) that exhibit enormous intra and intersexual size variation. Males bear an elongated rostrum used as a weapon in fights for mating opportunities. However, small males also employ sneaking behavior as an alternative reproductive tactic. We investigated sexual selection on size by tracking individual males and females daily over two 30‐day periods to measure long‐term mating success. We also assessed how survival and recapture probabilities vary with sex and size to determine whether there might be a survival cost associated with size. We found evidence for directional selection on size through higher mating success, but no apparent survival trade‐off. Instead, larger individuals mate more often and have a higher survival probability, suggesting an accumulation of benefits to bigger individuals. Furthermore, we found evidence of size assortative mating where males appear to selectively mate with bigger females. Larger and more competitive males secure matings with larger females more frequently than smaller males, which may further increase their fitness.

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“…Larvae bore in the wood of native trees, and the adults emerge during the warmer months (October–March) and aggregate on dead or dying trees. The species utilises numerous tree species as hosts, such as karaka ( Corynocarpus laevigatus ) and māhoe ( Melicytus ramiflorus ) (Painting and Holwell ).…”

Section: Methodsmentioning

confidence: 99%

Male‐biased sexual size dimorphism and sex ratio in the New Zealand Giraffe Weevil, Lasiorhynchus barbicornis (Fabricius, 1775) (Coleoptera: Brentidae)

2014

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Both the sex ratio and the extent of sexual size dimorphism (SSD) can have important implications for the mating system of a species. In particular, the sex that is limited (generally the female) is often the subject of intense competition, which can drive changes in behaviour and morphology to increase the competitive ability of the more abundant sex. The New Zealand giraffe weevil, Lasiorhynchus barbicornis (Fabricius, 1775), is a large and charismatic species found across much of New Zealand, but very little is known about its natural history. We determined the population structure and ecology of L. barbicornis from a single wild population over 3 years. L. barbicornis was found to be highly abundant in the warmer months, between November and May, but showed a peak in abundance in February and March in each year. The sex ratio was consistently male-biased throughout the breeding season (mean sex ratio between seasons 0.59 ± 0.02). Univariate and multivariate analyses showed that L. barbicornis is highly sexually size-dimorphic mostly because of the extreme elongation of the rostrum of the male. All body parts of the males were also found to be more variable in size than those of the females, particularly head length, as shown by higher coefficients of variation. There was, however, no significant seasonal variation in SSD. These data are crucial to gain an understanding of the ecology and of factors driving the mating system in this species. The male-biased sex ratio and SSD are key components of L. barbicornis ecology and are likely to have driven the highly competitive, defence-based mating system observed.

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Observations on the ecology and behaviour of the New Zealand giraffe weevil (Lasiorhynchus barbicornis)

Cited by 16 publications

References 7 publications

Weapon allometry varies with latitude in the New Zealand giraffe weevil

Weapon allometry varies with latitude in the New Zealand giraffe weevil

Directional selection on body size but no apparent survival cost to being large in wild New Zealand giraffe weevils

Male‐biased sexual size dimorphism and sex ratio in the New Zealand Giraffe Weevil, Lasiorhynchus barbicornis (Fabricius, 1775) (Coleoptera: Brentidae)

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