The Function of Delayed Plumage Maturation in Male Black-Headed Grosbeaks

The Auk ◽  
1988 ◽  
Vol 105 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Geoffrey E. Hill
Keyword(s):  
Adult Males ◽  
Subadult Male ◽  
Delayed Plumage Maturation ◽  
Breeding Populations ◽  
Female Mimicry ◽  
Wide Range ◽  
Plumage Maturation ◽  
Alternative Hypotheses ◽  
Males And Females ◽  
Study Sites

Abstract I used data from two breeding populations of Black-headed Grosbeaks (Pheucticus melanocephalus) in central New Mexico to test alternative hypotheses regarding the function of delayed plumage maturation in male passerines. Yearling male grosbeaks displayed a wide range of subadult plumage types, but most individuals were intermediate in appearance between adult males and females. Subadult male grosbeaks arrived on the study sites about 2 weeks after adult males, with no tendency for individuals with brighter or duller plumage to arrive first. Only a few of the most brightly plumaged subadult males defended territories and attracted females; most were nonterritorial floaters. All territories of subadult males were positioned outside clusters of adult male territories with few total neighbors. When I removed adult males from their territories, the territories remained empty. These results are not consistent with predictions of the female-mimicry hypothesis, but they are in accord with those of the cryptic hypothesis.

Why Are Waxwings “Waxy”? Delayed Plumage Maturation in the Cedar Waxwing

The Auk ◽  
1988 ◽  
Vol 105 (1) ◽  
pp. 61-69 ◽  
Author(s):  
D. James Mountjoy ◽  
Raleigh J. Robertson
Keyword(s):  
Status Signaling ◽  
Delayed Plumage Maturation ◽  
Female Mimicry ◽  
Bombycilla Cedrorum ◽  
Plumage Maturation ◽  
The Status ◽  
Males And Females ◽  
Second Year ◽  
Cedar Waxwing ◽  
Signaling Hypothesis

Abstract Cedar Waxwings (Bombycilla cedrorum) often have their secondaries tipped with red waxlike appendages, but a plausible hypothesis for the function of these tips has not been presented. Both males and females may have such tips, but second-year birds normally have none or only a few. This appears to be the first described instance of a passerine species to show distinctive delayed plumage maturation in both sexes. We found that waxwings mated assortatively with respect to the number of tips on the secondaries of the birds. Pairs of older birds (with high tip index scores) tended to nest earlier than younger (low tip index) birds. Older birds also had larger clutch/brood sizes and fledged more young. We suggest that the waxlike tips function as signals of age and status and that some combination of mate choice and competition for mates results in the observed assortative mating. Of the hypotheses proposed to explain the adaptive significance of delayed plumage maturation, two (the female-mimicry and cryptic hypotheses) are not confirmed in the case of the Cedar Waxwing, while the status-signaling hypothesis appears to offer the best explanation for the occurrence of delayed plumage maturation in this species.

Delayed plumage maturation in green‐backed flycatchers (Ficedula elisae): An evidence of female mimicry

Ethology ◽  
2018 ◽  
Vol 125 (1) ◽  
pp. 64-72 ◽  
Author(s):  
Gong Chen ◽  
Canwei Xia ◽  
Lu Dong ◽  
Nan Lyu ◽  
Yanyun Zhang
Keyword(s):  
Delayed Plumage Maturation ◽  
Female Mimicry ◽  
Plumage Maturation

scholarly journals Toxicological and biochemical effects of some insecticides on peach fly, Bactrocera zonata (Diptera: Tephritidae)

2011 ◽  
Vol 47 (No. 3) ◽  
pp. 121-130 ◽  
Author(s):  
Y.Y. Mosleh ◽  
L.H. Yousry ◽  
A. Alo-El-Elaa
Keyword(s):  
Fruit Fly ◽  
Post Treatment ◽  
Adult Males ◽  
Glutamic Oxaloacetic Transaminase ◽  
Peach Fruit ◽  
Biochemical Effects ◽  
Adult Females ◽  
Bactrocera Zonata ◽  
Wide Range ◽  
Males And Females

The peach fruit fly, Bactrocera zonata (Saunders, Diptera: Tephritidae), has been a serious pest in the last decade attacking a wide range of fruits in Egypt. The toxicity of Malathion, Diazinon, Methoxyfenozide and Lufenuron to adult males and females of B. zonata was studied under laboratory conditions. The results showed that Diazinon was the most toxic among the tested compounds followed by Malathion, Lufenuron and Methoxyfenozide. LC<sub>50</sub> values for adult males and females were 0.20 ppm, 0.09 ppm and 0.02 ppm (for males), 0.91 ppm, 0.14 ppm and 0,01 ppm (for females), respectively. The results showed that the level of glutamic oxaloacetic transaminase (GOT) of treated adult males and females in 24 h, 48 h, and 72 h post treatment increased compared to untreated adults. The highest activities of GOT in treated adult males in 24 h, 48 h, and 72 h were 92.11&micro;M, 101.99&micro;M and 112.21&micro;M pyruvate released &times; 10<sup>3</sup>/min/g FW (fresh weight), respectively, for Methoxyfenozide LC<sub>10</sub>, and in treated adult females after 24 h, 48 h, and 72 h they were 84.24&micro;M, 94.33&micro;M, and 111.12&micro;M pyruvate released &times; 10<sup>3</sup>/min/g FW, respectively, for Diazinon LC<sub>25</sub>. The activities of acetylcholine esterase of treated adults decreased compared to untreated adults. The highest activities of acid phosphatase in adult males after 24 h and 48 h were 249.43 &micro;g and 270.52 &micro;g AchI hydrolysed/min/g FW, respectively, for Methoxyfenozide LC<sub>25</sub>. The highest activities of alkaline phosphatase in adult males were 139.04 &micro;g, 175.67 &micro;g, and 199.29 &micro;g phenol &times; 10<sup>3</sup>/min/g FW for Malathion LC<sub>10</sub> and in adult females they were 123.31 &micro;g, 162.10 &micro;g and 199.59 &micro;g phenol.10<sup>3</sup>/min/g FW, respectively, for Lufenuron LC<sub>25</sub> in 24 h, 48 h, and 72 h post treatment.

scholarly journals Comparative toxicity of certain pesticides to peach fruit fly, Bactrocera zonata Saunders (Diptera: Tephritidae) under laboratory conditions

2011 ◽  
Vol 47 (No. 3) ◽  
pp. 115-120 ◽  
Author(s):  
Y.Y. Mosleh ◽  
S.F.M. Moussa ◽  
L.H.Y. Mohamed
Keyword(s):  
Fruit Fly ◽  
Post Treatment ◽  
Adult Males ◽  
Peach Fruit ◽  
Laboratory Conditions ◽  
Adult Females ◽  
Comparative Toxicity ◽  
Bactrocera Zonata ◽  
Wide Range ◽  
Males And Females

Peach fruit fly, Bactrocera zonata (Saunders) (Diptera: Tephritidae), has been a serious pest in the last decade attacking a wide range of fruits in Egypt. The toxicity of Malathion, Diazinon, Methoxyfenozide, and Lufenuron to adult males and females of Bactrocera zonata was studied under laboratory conditions. Diazinon was the most toxic among the tested compounds followed by Malathion, Lufenuron and Methoxyfenozide to Bactrocera zonata at 24 h post treatment, the respective LC<sub>50</sub> values were 0.20 ppm, 0.48ppm, 8.97ppm, and 9.73ppm for males and 0.26 ppm, 0.91ppm, 11.26ppm, and 14.12ppm for females. At 48 h post treatment Diazinon was the most toxic followed by Malathion, Methoxyfenozide and Lufenuron to Bactrocera zonata, LC<sub>50</sub> values were 0.09ppm, 0.34ppm, 1.60ppm, and 1.88 ppm for males and 0.14 ppm, 0.44ppm, 1.68ppm and 2.17 ppm for females. At 72&nbsp;h post treatment Diazinon was the most toxic followed by Malathion, Lufenuron and Methoxyfenozide to Bactrocera zonata, LC<sub>50</sub> values were 0.02 ppm, 0.13ppm, 0.22ppm and 0.51ppm for males and 0.07 ppm, 0.16ppm, 0.55 ppm and 0.62 ppm for females. It is observed that LC<sub>50</sub> values for treated adult females increased more than in the treated adult males at 24 h, 48 h, and 72 h post treatment. It means that the adult males were more susceptible to the tested insecticides than the adult females.

scholarly journals Dispersal characteristics of swift foxes

2004 ◽  
Vol 82 (12) ◽  
pp. 1837-1842 ◽  
Author(s):  
Jan F Kamler ◽  
Warren B Ballard ◽  
Eric M Gese ◽  
Robert L Harrison ◽  
Seija M Karki
Keyword(s):  
New Mexico ◽  
Adult Males ◽  
Dispersal Patterns ◽  
Vulpes Velox ◽  
Males And Females ◽  
Study Sites ◽  
Adult Dispersal ◽  
Juvenile Males ◽  
Dispersal Characteristics

From 1997 to 2001, we monitored movements of 109 adult and 114 juvenile swift foxes, Vulpes velox (Say, 1823), at study sites in Colorado, New Mexico, and Texas to determine patterns of dispersal. Significantly more male (93%) than female (58%) juveniles dispersed, and both sexes had similar bimodal dispersal patterns with peaks in September–October and January–February. Adult dispersal occurred more evenly throughout the year, and significantly more male (32%) than female (5%) adults dispersed. Adult males tended to disperse after the death of their mate. Of dispersing foxes with known fates, settlement percentages in new territories were similar between juvenile males and females (40% overall), but they were significantly lower than for adults (89%). All other dispersing foxes with known fates died. Among juvenile females with known fates, similar percentages of philopatric and dispersing foxes reproduced as yearlings (50% overall), so the benefits of dispersal versus philopatry were not clear. Although rarely reported for other species, adult males were an important dispersal cohort in swift foxes (43% of male dispersals and 25% of all dispersals). Because of the female-biased philopatry among swift foxes, dispersal of adult males likely decreased the chances for inbreeding (e.g., father–daughter breeding).

Sign in / Sign up

Export Citation Format

Share Document