Dragonflies are predators, both in their aquatic larval stage, when they are known as nymphs or naiads, and as adults. Several years of their lives are spent as nymphs living in fresh water; the adults may be on the wing for just a few days or weeks. They are fast, agile fliers, sometimes migrating across oceans, and are often found near water. They have a uniquely complex mode of reproduction involving indirect insemination, delayed fertilization, and sperm competition. During mating, the male grasps the female at the back of the head or on the prothorax, and the female curls her abdomen under her body to pick up sperm from the male's secondary genitalia at the front of his abdomen, forming the heart or wheel posture.
圖片編號:
66474049
拍攝者:
Suketasandip
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授權類型 | 尺寸 | 像素 | 格式 | 點數 | |
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標準授權 | XS | 320 x 480 | JPG | 13 | |
標準授權 | S | 533 x 800 | JPG | 15 | |
標準授權 | M | 1414 x 2121 | JPG | 18 | |
標準授權 | L | 1825 x 2738 | JPG | 20 | |
標準授權 | XL | 2400 x 3600 | JPG | 22 | |
標準授權 | MAX | 2828 x 4242 | JPG | 23 | |
標準授權 | TIFF | 3394 x 5091 | TIF | 39 | |
進階授權 | WEL | 2828 x 4242 | JPG | 88 | |
進階授權 | PEL | 2828 x 4242 | JPG | 88 | |
進階授權 | UEL | 2828 x 4242 | JPG | 88 |
XS
S
M
L
XL
MAX
TIFF
WEL
PEL
UEL
標準授權 | 320 x 480 px | JPG | 13 點 |
標準授權 | 533 x 800 px | JPG | 15 點 |
標準授權 | 1414 x 2121 px | JPG | 18 點 |
標準授權 | 1825 x 2738 px | JPG | 20 點 |
標準授權 | 2400 x 3600 px | JPG | 22 點 |
標準授權 | 2828 x 4242 px | JPG | 23 點 |
標準授權 | 3394 x 5091 px | TIF | 39 點 |
進階授權 | 2828 x 4242 px | JPG | 88 點 |
進階授權 | 2828 x 4242 px | JPG | 88 點 |
進階授權 | 2828 x 4242 px | JPG | 88 點 |