FGC - 670.1 (3/94) A PETITION TO THE STATE OF CALIFORNIA FISH AND GAME COMMISSION For action pursuant to Section 670.1, Title 14, California Code of Regulations (CCR) and Sections 2072 and 2073 of the Fish and Game Code relating to listing and delisting endangered and threatened species of plants and animals. I. SPECIES BEING PETITIONED: 1. Common Name: Crotch bumble bee Scientific Name: Bombus crotchii 2. Common Name: Franklin’s bumble bee Scientific Name: Bombus franklini 3. Common Name: Suckley cuckoo bumble bee Scientific Name: Bombus suckleyi 4. Common Name: Western bumble bee Scientific Name: Bombus occidentalis occidentalis II. RECOMMENDED ACTION: 1. Common Name: Crotch bumble bee As Endangered X Scientific Name: Bombus crotchii 2. Common Name: Franklin’s bumble bee As Endangered X Scientific Name: Bombus franklini 3. Common Name: Suckley cuckoo bumble bee As Endangered X Scientific Name: Bombus suckleyi 4. Common Name: Western bumble bee As Endangered X Scientific Name: Bombus occidentalis occidentalis III. AUTHOR OF PETITION: Name: The Xerces Society, including: Rich Hatfield, Sarina Jepsen, Sarah Foltz Jordan, Michele Blackburn, Aimée Code Address: 628 NE Broadway, Portland, OR 97232 Phone Number: 503-232-6639 1 I hereby certify that, to the best of my knowledge, all statements made in this petition are true and complete. Signature: Date: 16 October 2018 FGC - 670.1 (3/94) 2 A PETITION TO THE STATE OF CALIFORNIA FISH AND GAME COMMISSION TO LIST The Crotch bumble bee (Bombus crotchii), Franklin’s bumble bee (Bombus franklini), Suckley cuckoo bumble bee (Bombus suckleyi), and western bumble bee (Bombus occidentalis occidentalis) as Endangered under the California Endangered Species Act Bombus crotchii, by Stephanie McKnight, the Xerces Society (top left); Bombus franklini, by Pete Schroeder (top right); Bombus occidentalis occidentalis, by Rich Hatfield, the Xerces Society (bottom left); Bombus suckleyi, by Hadel Go/www.discoverlife.org (bottom right). Submitted by The Xerces Society for Invertebrate Conservation, Defenders of Wildlife, Center for Food Safety October 2018 3 TABLE OF CONTENTS I. EXECUTIVE SUMMARY ................................................................................................... 5 II. POPULATION TRENDS, ABUNDANCE, RANGE, AND DISTRIBUTION .................. 6 Current Conservation Status ................................................................................................... 6 Changes in Range, Distribution, and Relative Abundance ..................................................... 8 Methods Used ......................................................................................................................... 21 Analyses ................................................................................................................................ 21 III. LIFE HISTORY (SPECIES DESCRIPTION, BIOLOGY, AND ECOLOGY) ............... 23 Bumble Bee Biology ............................................................................................................. 23 Bumble Bee Pollination Ecology .......................................................................................... 23 Crotch bumble bee (Bombus crotchii) Cresson 1878 ........................................................... 24 Franklin’s bumble bee (Bombus franklini) (Frison, 1921) ................................................... 25 Western bumble bee (Bombus occidentalis occidentalis) Greene, 1858 .............................. 27 Suckley Cuckoo Bumble Bee (Bombus suckleyi) Greene, 1860 .......................................... 28 IV. KIND OF HABITAT NECESSARY FOR SURVIVAL ................................................. 30 Habitat Requirements............................................................................................................ 30 Crotch Bumble Bee (Bombus crotchii) Habitat Requirements ............................................. 32 Franklin’s Bumble Bee (Bombus franklini) Habitat Requirements ...................................... 33 Western Bumble Bee (Bombus occidentalis occidentalis) Habitat Requirements ............... 33 Suckley Cuckoo Bumble Bee (Bombus suckleyi) Habitat Requirements ............................. 35 V. FACTORS AFFECTING ABILITY TO SURVIVE AND REPRODUCE....................... 37 A. Present or Threatened Modification or Destruction of Habitat ........................................ 37 B. Overexploitation ............................................................................................................... 44 C. Competition with Managed Honey Bees ......................................................................... 46 D. Disease ............................................................................................................................. 47 E. Other Natural Events or Human-related Activities .......................................................... 56 VI. DEGREE AND IMMEDIACY OF THREAT ................................................................. 62 VII. IMPACT OF EXISTING MANAGEMENT EFFORTS ................................................ 63 Crotch Bumble Bee (Bombus crotchii) ................................................................................. 63 Franklin’s bumble bee (Bombus franklini) ........................................................................... 63 Western bumble bee (Bombus occidentalis occidentalis) .................................................... 64 Suckley bumble bee (Bombus suckleyi) ................................................................................ 64 VIII. SUGGESTIONS FOR FUTURE MANAGEMENT ..................................................... 65 General Guidelines for Bumble Bees ................................................................................... 65 Creating High-Quality Habitat .............................................................................................. 65 4 Using Pesticides .................................................................................................................... 68 Commercial Use of Bumble Bees ......................................................................................... 69 Honey Bees ........................................................................................................................... 69 Inventory, Research & Management Needs ......................................................................... 71 IX. INADEQUACY OF EXISTING REGULATORY MECHANISMS .............................. 73 Disease .................................................................................................................................. 73 Pesticide Regulations ............................................................................................................ 76 X. AVAILABILITY AND SOURCES OF INFORMATION ............................................... 79 Literature Cited ..................................................................................................................... 79 Personal Communications .................................................................................................. 113 XI. DETAILED DISTRIBUTION MAPS ............................................................................ 114 Crotch bumble bee (Bombus crotchii) Global Distribution ................................................ 114 Franklin’s bumble bee (Bombus franklini) Global Distribution ......................................... 115 Western bumble bee (Bombus occidentalis occidentalis) California Distribution ............. 116 Western bumble bee (Bombus occidentalis occidentalis) Global Distribution .................. 117 Suckley Cuckoo Bumble Bee (Bombus suckleyi) California Distribution ......................... 118 Suckley Cuckoo Bumble Bee (Bombus suckleyi) Global Distribution ............................... 119 I. EXECUTIVE SUMMARY The Crotch bumble bee (Bombus crotchii), Franklin’s bumble bee (Bombus franklini), Suckley cuckoo bumble bee (Bombus suckleyi), and western bumble bee (Bombus occidentalis occidentalis) are endangered with extinction throughout their ranges, including in California. Recent research has shown a significant reduction in both the range and relative abundance of these species, and where they still persist, they are far less common than they were historically. The Crotch bumble bee (Bombus crotchii) was historically common in the southern two-thirds of California, but now appears to be absent from most of it, especially in the center of its historic range (Hatfield et al. 2014; Richardson et al. 2014); analyses suggests sharp declines in both relative abundance (98% decline) and persistence (80% decline) over the last ten years. Franklin’s bumble bee (Bombus franklini) is in imminent danger of extinction and notably has the most limited geographic distribution of any bumble bee in North America and possibly the world (Williams 1998). Extensive surveys since 1998 have demonstrated that there has been a precipitous decline in the number of individuals and localities in the past several decades; this species has not been seen in California since 1998, and has not been seen anywhere since 2006. The western bumble bee (Bombus occidentalis occidentalis) has recently undergone a dramatic decline in abundance and distribution, and is no longer present across much of its historic range. Declines suggest it has been lost from 53% of its historic range and has experienced an 84% decline in relative abundance (Hatfield et al., unpublished data); in 5